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<!DOCTYPE html><html lang="zh-CN"><head><meta charset="UTF-8"><meta name="viewport" content="width=device-width"><meta name="theme-color" content="#222"><meta name="generator" content="Hexo 6.3.0"><link rel="preconnect" href="https://fonts.googleapis.com" crossorigin><link rel="preconnect" href="https://cdnjs.cloudflare.com" crossorigin><link rel="apple-touch-icon" sizes="180x180" href="/images/apple-touch-icon-next.png"><link rel="icon" type="image/png" sizes="32x32" href="/images/favicon-32x32-next.png"><link rel="icon" type="image/png" sizes="16x16" href="/images/favicon-16x16-next.png"><link rel="mask-icon" href="/images/logo.svg" color="#222"><meta name="google-site-verification" content="2X6S9P7CAjXjVvw8YyQR8pCu-B0oEu7O9quLgxXuWyA"><meta name="baidu-site-verification" content="dV8JGNzi0c"><script>setTimeout(function(){var 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${time} 毫秒）","hits":"找到 ${hits} 个搜索结果"},"path":"/search.xml","localsearch":{"enable":true,"trigger":"auto","top_n_per_article":1,"unescape":true,"preload":true}}</script><script src="/js/config.js"></script><meta name="description" content="learn from zero,技术博客，Nicksxs，史学森"><meta property="og:type" content="website"><meta property="og:title" content="Nicksxs&#39;s Blog"><meta property="og:url" content="https://nicksxs.me/index.html"><meta property="og:site_name" content="Nicksxs&#39;s Blog"><meta property="og:description" content="learn from zero,技术博客，Nicksxs，史学森"><meta property="og:locale" content="zh_CN"><meta property="article:author" content="Nicksxs"><meta property="article:tag" content="Nicksxs,史学森,米方方,米方方的男朋友,森哥"><meta name="twitter:card" content="summary"><link rel="canonical" href="https://nicksxs.me/"><script class="next-config" data-name="page" type="application/json">{"sidebar":"","isHome":true,"isPost":false,"lang":"zh-CN","comments":"","permalink":"","path":"index.html","title":""}</script><script class="next-config" data-name="calendar" type="application/json">""</script><title>Nicksxs's Blog - What hurts more, the pain of hard work or the pain of regret?</title><script async src="https://www.googletagmanager.com/gtag/js?id=UA-61358619-1"></script><script class="next-config" data-name="google_analytics" type="application/json">{"tracking_id":"UA-61358619-1","only_pageview":false}</script><script src="/js/third-party/analytics/google-analytics.js"></script><script src="/js/third-party/analytics/baidu-analytics.js"></script><script async src="https://hm.baidu.com/hm.js?20f33b3c0c0eff9b1522999c0015646d"></script><noscript><link rel="stylesheet" href="/css/noscript.css"></noscript><link rel="alternate" href="/atom.xml" title="Nicksxs's Blog" type="application/atom+xml"></head><body itemscope itemtype="http://schema.org/WebPage" class="use-motion"><div class="headband"></div><main class="main"><div class="column"><header class="header" itemscope itemtype="http://schema.org/WPHeader"><div class="site-brand-container"><div class="site-nav-toggle"><div class="toggle" aria-label="切换导航栏" role="button"><span class="toggle-line"></span> <span class="toggle-line"></span> <span class="toggle-line"></span></div></div><div class="site-meta"><a href="/" class="brand" rel="start"><i class="logo-line"></i><h1 class="site-title">Nicksxs's Blog</h1><i class="logo-line"></i></a><p class="site-subtitle" itemprop="description">What hurts more, the pain of hard work or the pain of regret?</p></div><div class="site-nav-right"><div class="toggle popup-trigger" aria-label="搜索" role="button"><i class="fa fa-search fa-fw fa-lg"></i></div></div></div><nav class="site-nav"><ul class="main-menu menu"><li class="menu-item menu-item-home"><a href="/" rel="section"><i class="fa fa-home 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class="search-pop-overlay"><div class="popup search-popup"><div class="search-header"><span class="search-icon"><i class="fa fa-search"></i></span><div class="search-input-container"><input autocomplete="off" autocapitalize="off" maxlength="80" placeholder="搜索..." spellcheck="false" type="search" class="search-input"></div><span class="popup-btn-close" role="button"><i class="fa fa-times-circle"></i></span></div><div class="search-result-container no-result"><div class="search-result-icon"><i class="fa fa-spinner fa-pulse fa-5x"></i></div></div></div></div></header><aside class="sidebar"><div class="sidebar-inner sidebar-overview-active"><ul class="sidebar-nav"><li class="sidebar-nav-toc">文章目录</li><li class="sidebar-nav-overview">站点概览</li></ul><div class="sidebar-panel-container"><div class="post-toc-wrap sidebar-panel"></div><div class="site-overview-wrap sidebar-panel"><div class="site-author animated" itemprop="author" itemscope itemtype="http://schema.org/Person"><img class="site-author-image" itemprop="image" alt="Nicksxs" src="/uploads/avatar.jpg"><p class="site-author-name" itemprop="name">Nicksxs</p><div class="site-description" itemprop="description">learn from zero,技术博客，Nicksxs，史学森</div></div><div class="site-state-wrap animated"><nav class="site-state"><div class="site-state-item site-state-posts"><a href="/archives/"><span class="site-state-item-count">194</span> <span class="site-state-item-name">日志</span></a></div><div class="site-state-item site-state-categories"><a href="/categories/"><span class="site-state-item-count">148</span> <span class="site-state-item-name">分类</span></a></div><div class="site-state-item site-state-tags"><a href="/tags/"><span class="site-state-item-count">287</span> <span class="site-state-item-name">标签</span></a></div></nav></div><div class="links-of-author animated"><span class="links-of-author-item"><a href="https://github.com/nicksxs" title="GitHub → https:&#x2F;&#x2F;github.com&#x2F;nicksxs" rel="noopener 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rel="tag">Shift 2D Grid</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/Singleton/" rel="tag">Singleton</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/Spring/" rel="tag">Spring</a><span class="tag-list-count">6</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/Spring-Event/" rel="tag">Spring Event</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/SpringBoot/" rel="tag">SpringBoot</a><span class="tag-list-count">4</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/Sql%E6%B3%A8%E5%85%A5/" rel="tag">Sql注入</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/Stream/" rel="tag">Stream</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/Synchronized/" rel="tag">Synchronized</a><span class="tag-list-count">2</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/Thread-dump/" rel="tag">Thread dump</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/ThreadLocal/" rel="tag">ThreadLocal</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/ThreadPool/" rel="tag">ThreadPool</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/Tomcat/" rel="tag">Tomcat</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/Trapping-Rain-Water/" rel="tag">Trapping Rain Water</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/WeakReference/" rel="tag">WeakReference</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/Web/" rel="tag">Web</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/Webhook/" rel="tag">Webhook</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/WordPress/" rel="tag">WordPress</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/aqs/" rel="tag">aqs</a><span class="tag-list-count">3</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/await/" rel="tag">await</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/bloom-filter/" rel="tag">bloom filter</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/c/" rel="tag">c++</a><span class="tag-list-count">14</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/cglib/" rel="tag">cglib</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/cgroup/" rel="tag">cgroup</a><span class="tag-list-count">2</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/cluster/" rel="tag">cluster</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/condition/" rel="tag">condition</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/docker/" rel="tag">docker</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/dp/" rel="tag">dp</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/dubbo/" rel="tag">dubbo</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/echo/" rel="tag">echo</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/environment/" rel="tag">environment</a><span class="tag-list-count">2</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/gap-lock/" rel="tag">gap lock</a><span class="tag-list-count">2</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/gc/" rel="tag">gc</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/git/" rel="tag">git</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/grep/" rel="tag">grep</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/hadoop/" rel="tag">hadoop</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/icu4c/" rel="tag">icu4c</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/im/" rel="tag">im</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/is-not-null/" rel="tag">is not null</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/is-null/" rel="tag">is null</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/j-u-c/" rel="tag">j.u.c</a><span class="tag-list-count">2</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/java/" rel="tag">java</a><span class="tag-list-count">33</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/jvm/" rel="tag">jvm</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/leetcode/" rel="tag">leetcode</a><span class="tag-list-count">40</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/leetcode-155/" rel="tag">leetcode 155</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/linked-list/" rel="tag">linked list</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/linux/" rel="tag">linux</a><span class="tag-list-count">3</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/lock/" rel="tag">lock</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/mfc/" rel="tag">mfc</a><span class="tag-list-count">2</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/min-stack/" rel="tag">min stack</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/mq/" rel="tag">mq</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/mvcc/" rel="tag">mvcc</a><span class="tag-list-count">3</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/mysql/" rel="tag">mysql</a><span class="tag-list-count">6</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/namespace/" rel="tag">namespace</a><span class="tag-list-count">3</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/next-key-lock/" rel="tag">next-key lock</a><span class="tag-list-count">2</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/nginx/" rel="tag">nginx</a><span class="tag-list-count">3</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/nullsfirst/" rel="tag">nullsfirst</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/openresty/" rel="tag">openresty</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/php/" rel="tag">php</a><span class="tag-list-count">4</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/powershell/" rel="tag">powershell</a><span class="tag-list-count">2</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/procedure/" rel="tag">procedure</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/python/" rel="tag">python</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/read-view/" rel="tag">read view</a><span class="tag-list-count">3</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/redis/" rel="tag">redis</a><span class="tag-list-count">12</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/scp/" rel="tag">scp</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/signal/" rel="tag">signal</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/sort/" rel="tag">sort</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/spark/" rel="tag">spark</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/ssh/" rel="tag">ssh</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/stack/" rel="tag">stack</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/stream/" rel="tag">stream</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/string/" rel="tag">string</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/swoole/" rel="tag">swoole</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/top/" rel="tag">top</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/uname/" rel="tag">uname</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/unlock/" rel="tag">unlock</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/utf8/" rel="tag">utf8</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/utf8mb4/" rel="tag">utf8mb4</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/utf8mb4-0900-ai-ci/" rel="tag">utf8mb4_0900_ai_ci</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/utf8mb4-general-ci/" rel="tag">utf8mb4_general_ci</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/utf8mb4-unicode-ci/" rel="tag">utf8mb4_unicode_ci</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/value/" rel="tag">value</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/websocket/" rel="tag">websocket</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/zookeeper/" rel="tag">zookeeper</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/zsh/" rel="tag">zsh</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/%E4%B8%89%E9%98%B6%E6%AE%B5%E6%8F%90%E4%BA%A4/" rel="tag">三阶段提交</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/%E4%B8%8D%E5%8F%AF%E5%8F%98%E5%BC%95%E7%94%A8/" rel="tag">不可变引用</a><span class="tag-list-count">2</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/%E4%B8%9C%E4%BA%AC%E5%A5%A5%E8%BF%90%E4%BC%9A/" rel="tag">东京奥运会</a><span class="tag-list-count">2</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/%E4%B8%A4%E9%98%B6%E6%AE%B5%E6%8F%90%E4%BA%A4/" rel="tag">两阶段提交</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/%E4%B8%AD%E5%B1%B1%E8%B7%AF/" rel="tag">中山路</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/%E4%B8%AD%E5%BA%8F/" rel="tag">中序</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/%E4%B8%AD%E9%97%B4%E4%BB%B6/" rel="tag">中间件</a><span class="tag-list-count">4</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/%E4%B8%BE%E9%87%8D/" rel="tag">举重</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/%E4%B9%92%E4%B9%93%E7%90%83/" rel="tag">乒乓球</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/%E4%BA%8B%E5%8A%A1/" rel="tag">事务</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/%E4%BA%8C%E5%8F%89%E6%A0%91/" rel="tag">二叉树</a><span class="tag-list-count">3</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/%E4%BA%92%E6%96%A5%E9%94%81/" rel="tag">互斥锁</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/%E4%BB%A3%E7%A0%81%E9%A2%98%E8%A7%A3/" rel="tag">代码题解</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/%E4%BF%AE%E7%94%B5%E8%84%91%E7%9A%84/" rel="tag">修电脑的</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/%E5%81%8F%E5%90%91%E9%94%81/" rel="tag">偏向锁</a><span class="tag-list-count">2</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/%E5%81%A5%E5%BA%B7%E7%A0%81/" rel="tag">健康码</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/%E5%85%AC%E4%BA%A4/" rel="tag">公交</a><span class="tag-list-count">3</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/%E5%85%AC%E4%BA%A4%E8%BD%A6/" rel="tag">公交车</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/%E5%86%85%E5%AD%98%E5%88%86%E5%B8%83/" rel="tag">内存分布</a><span class="tag-list-count">3</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/%E5%86%85%E5%AD%98%E6%B3%84%E6%BC%8F/" rel="tag">内存泄漏</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/%E5%87%86%E5%A4%87/" rel="tag">准备</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/%E5%87%8F%E8%82%A5/" rel="tag">减肥</a><span class="tag-list-count">6</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/%E5%88%86%E5%B8%83%E5%BC%8F%E4%BA%8B%E5%8A%A1/" rel="tag">分布式事务</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/%E5%88%86%E5%B8%83%E5%BC%8F%E9%94%81/" rel="tag">分布式锁</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/%E5%88%87%E7%89%87/" rel="tag">切片</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/%E5%88%9D%E5%A7%8B%E5%8C%96/" rel="tag">初始化</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/%E5%89%8A%E5%B3%B0%E5%A1%AB%E8%B0%B7/" rel="tag">削峰填谷</a><span class="tag-list-count">4</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/%E5%89%8D%E5%BA%8F/" rel="tag">前序</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/%E5%8A%A0%E5%A1%9E/" rel="tag">加塞</a><span class="tag-list-count">3</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/%E5%8A%A0%E8%BD%BD/" rel="tag">加载</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/%E5%8D%95%E4%BE%8B/" rel="tag">单例</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/%E5%8D%9A%E5%AE%A2%EF%BC%8C%E6%96%87%E7%AB%A0/" rel="tag">博客，文章</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/%E5%8E%A6%E9%97%A8/" rel="tag">厦门</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/%E5%8F%8C%E4%BA%B2%E5%A7%94%E6%B4%BE/" rel="tag">双亲委派</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/%E5%8F%91%E8%A1%8C%E7%89%88/" rel="tag">发行版</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/%E5%8F%A3%E7%BD%A9/" rel="tag">口罩</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/%E5%8F%AF%E5%8F%98%E5%BC%95%E7%94%A8/" rel="tag">可变引用</a><span class="tag-list-count">2</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/%E5%90%90%E6%A7%BD/" rel="tag">吐槽</a><span class="tag-list-count">2</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/%E5%9B%A4%E7%89%A9%E8%B5%84/" rel="tag">囤物资</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/%E5%9E%83%E5%9C%BE%E5%9B%9E%E6%94%B6/" rel="tag">垃圾回收</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/%E5%9F%BA%E7%A1%80%E8%AE%BE%E6%96%BD/" rel="tag">基础设施</a><span class="tag-list-count">2</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/%E5%A4%A7%E6%89%AB%E9%99%A4/" rel="tag">大扫除</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/%E5%AD%97%E7%AC%A6%E9%9B%86/" rel="tag">字符集</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/%E5%AE%89%E5%85%A8/" rel="tag">安全</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/%E5%AE%B9%E9%94%99%E6%9C%BA%E5%88%B6/" rel="tag">容错机制</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/%E5%AF%84%E7%94%9F%E8%99%AB/" rel="tag">寄生虫</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/%E5%B0%84%E5%87%BB/" rel="tag">射击</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/%E5%B0%8F%E6%8A%80%E5%B7%A7/" rel="tag">小技巧</a><span class="tag-list-count">5</span></li><li class="tag-list-item"><a class="tag-list-link" 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href="/tags/%E6%89%93%E5%8D%A1/" rel="tag">打卡</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/%E6%89%B6%E6%A2%AF/" rel="tag">扶梯</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/%E6%8A%80%E6%9C%AF/" rel="tag">技术</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/%E6%8B%96%E6%9B%B4/" rel="tag">拖更</a><span class="tag-list-count">2</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/%E6%8D%A2%E8%BD%A6%E7%89%8C/" rel="tag">换车牌</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/%E6%8E%92%E5%BA%8F/" rel="tag">排序</a><span class="tag-list-count">2</span></li><li class="tag-list-item"><a class="tag-list-link" href="/tags/%E6%8E%A5%E9%9B%A8%E6%B0%B4/" rel="tag">接雨水</a><span class="tag-list-count">1</span></li><li class="tag-list-item"><a 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itemprop="author" itemscope itemtype="http://schema.org/Person"><meta itemprop="image" content="/uploads/avatar.jpg"><meta itemprop="name" content="Nicksxs"></span><span hidden itemprop="publisher" itemscope itemtype="http://schema.org/Organization"><meta itemprop="name" content="Nicksxs's Blog"><meta itemprop="description" content="learn from zero,技术博客，Nicksxs，史学森"></span><span hidden itemprop="post" itemscope itemtype="http://schema.org/CreativeWork"><meta itemprop="name" content="undefined | Nicksxs's Blog"><meta itemprop="description" content=""></span><header class="post-header"><h2 class="post-title" itemprop="name headline"><a href="/2023/01/15/2022-%E5%B9%B4%E7%BB%88%E6%80%BB%E7%BB%93/" class="post-title-link" itemprop="url">2022 年终总结</a></h2><div class="post-meta-container"><div class="post-meta"><span class="post-meta-item"><span class="post-meta-item-icon"><i class="far fa-calendar"></i> </span><span class="post-meta-item-text">发表于</span> <time title="创建时间：2023-01-15 13:45:17 / 修改时间：13:45:18" itemprop="dateCreated datePublished" datetime="2023-01-15T13:45:17+08:00">2023-01-15</time> </span><span class="post-meta-item"><span class="post-meta-item-icon"><i class="far fa-folder"></i> </span><span class="post-meta-item-text">分类于</span> <span itemprop="about" itemscope itemtype="http://schema.org/Thing"><a href="/categories/%E7%94%9F%E6%B4%BB/" itemprop="url" rel="index"><span itemprop="name">生活</span></a> </span>， <span itemprop="about" itemscope itemtype="http://schema.org/Thing"><a href="/categories/%E7%94%9F%E6%B4%BB/%E5%B9%B4%E7%BB%88%E6%80%BB%E7%BB%93/" itemprop="url" rel="index"><span itemprop="name">年终总结</span></a> </span></span><span id="/2023/01/15/2022-%E5%B9%B4%E7%BB%88%E6%80%BB%E7%BB%93/" class="post-meta-item leancloud_visitors" data-flag-title="2022 年终总结" title="阅读次数"><span class="post-meta-item-icon"><i class="far fa-eye"></i> </span><span class="post-meta-item-text">阅读次数：</span> <span class="leancloud-visitors-count"></span> </span><span class="post-meta-item"><span class="post-meta-item-icon"><i class="far fa-comment"></i> </span><span class="post-meta-item-text">Disqus：</span> <a title="disqus" href="/2023/01/15/2022-%E5%B9%B4%E7%BB%88%E6%80%BB%E7%BB%93/#disqus_thread" itemprop="discussionUrl"><span class="post-comments-count disqus-comment-count" data-disqus-identifier="2023/01/15/2022-年终总结/" itemprop="commentCount"></span></a></span></div></div></header><div class="post-body" itemprop="articleBody"><p>一年又一年，时间匆匆，这一年过得不太容易，很多事情都是来得猝不及防，很多规划也照例是没有完成，今年更多了一些，又是比较丧的一篇总结</p><div class="post-button"><a class="btn" href="/2023/01/15/2022-%E5%B9%B4%E7%BB%88%E6%80%BB%E7%BB%93/#more" rel="contents">阅读全文 &raquo;</a></div></div><footer class="post-footer"><div class="post-eof"></div></footer></article></div><div class="post-block"><article itemscope itemtype="http://schema.org/Article" class="post-content"><link itemprop="mainEntityOfPage" href="https://nicksxs.me/2023/01/08/mybatis%E7%B3%BB%E5%88%97-dataSource%E8%A7%A3%E6%9E%90/"><span hidden itemprop="author" itemscope itemtype="http://schema.org/Person"><meta itemprop="image" content="/uploads/avatar.jpg"><meta itemprop="name" content="Nicksxs"></span><span hidden itemprop="publisher" itemscope itemtype="http://schema.org/Organization"><meta itemprop="name" content="Nicksxs's Blog"><meta itemprop="description" content="learn from zero,技术博客，Nicksxs，史学森"></span><span hidden itemprop="post" itemscope itemtype="http://schema.org/CreativeWork"><meta itemprop="name" content="undefined | Nicksxs's Blog"><meta itemprop="description" content=""></span><header class="post-header"><h2 class="post-title" itemprop="name headline"><a href="/2023/01/08/mybatis%E7%B3%BB%E5%88%97-dataSource%E8%A7%A3%E6%9E%90/" class="post-title-link" itemprop="url">mybatis系列-dataSource解析</a></h2><div class="post-meta-container"><div class="post-meta"><span class="post-meta-item"><span class="post-meta-item-icon"><i class="far fa-calendar"></i> </span><span class="post-meta-item-text">发表于</span> <time title="创建时间：2023-01-08 20:35:14" itemprop="dateCreated datePublished" datetime="2023-01-08T20:35:14+08:00">2023-01-08</time> </span><span class="post-meta-item"><span class="post-meta-item-icon"><i class="far fa-folder"></i> </span><span class="post-meta-item-text">分类于</span> <span itemprop="about" itemscope itemtype="http://schema.org/Thing"><a href="/categories/Java/" itemprop="url" rel="index"><span itemprop="name">Java</span></a> </span>， <span itemprop="about" itemscope itemtype="http://schema.org/Thing"><a href="/categories/Java/Mybatis/" itemprop="url" rel="index"><span itemprop="name">Mybatis</span></a> </span></span><span id="/2023/01/08/mybatis%E7%B3%BB%E5%88%97-dataSource%E8%A7%A3%E6%9E%90/" class="post-meta-item leancloud_visitors" data-flag-title="mybatis系列-dataSource解析" title="阅读次数"><span class="post-meta-item-icon"><i class="far fa-eye"></i> </span><span class="post-meta-item-text">阅读次数：</span> <span class="leancloud-visitors-count"></span> </span><span class="post-meta-item"><span class="post-meta-item-icon"><i class="far fa-comment"></i> </span><span class="post-meta-item-text">Disqus：</span> <a title="disqus" href="/2023/01/08/mybatis%E7%B3%BB%E5%88%97-dataSource%E8%A7%A3%E6%9E%90/#disqus_thread" itemprop="discussionUrl"><span class="post-comments-count disqus-comment-count" data-disqus-identifier="2023/01/08/mybatis系列-dataSource解析/" itemprop="commentCount"></span></a></span></div></div></header><div class="post-body" itemprop="articleBody"><p>DataSource 作为数据库查询的最重要的数据源，在 mybatis 中也展开来说下<br>首先是解析的过程</p><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token class-name">SqlSessionFactory</span> sqlSessionFactory <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">SqlSessionFactoryBuilder</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">build</span><span class="token punctuation">(</span>inputStream<span class="token punctuation">)</span><span class="token punctuation">;</span><span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><p>在构建 SqlSessionFactory 也就是 DefaultSqlSessionFactory 的时候，</p><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token keyword">public</span> <span class="token class-name">SqlSessionFactory</span> <span class="token function">build</span><span class="token punctuation">(</span><span class="token class-name">InputStream</span> inputStream<span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">return</span> <span class="token function">build</span><span class="token punctuation">(</span>inputStream<span class="token punctuation">,</span> <span class="token keyword">null</span><span class="token punctuation">,</span> <span class="token keyword">null</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token keyword">public</span> <span class="token class-name">SqlSessionFactory</span> <span class="token function">build</span><span class="token punctuation">(</span><span class="token class-name">InputStream</span> inputStream<span class="token punctuation">,</span> <span class="token class-name">String</span> environment<span class="token punctuation">,</span> <span class="token class-name">Properties</span> properties<span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">try</span> <span class="token punctuation">&#123;</span>
<span class="token class-name">XMLConfigBuilder</span> parser <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">XMLConfigBuilder</span><span class="token punctuation">(</span>inputStream<span class="token punctuation">,</span> environment<span class="token punctuation">,</span> properties<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">return</span> <span class="token function">build</span><span class="token punctuation">(</span>parser<span class="token punctuation">.</span><span class="token function">parse</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span> <span class="token keyword">catch</span> <span class="token punctuation">(</span><span class="token class-name">Exception</span> e<span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">throw</span> <span class="token class-name">ExceptionFactory</span><span class="token punctuation">.</span><span class="token function">wrapException</span><span class="token punctuation">(</span><span class="token string">"Error building SqlSession."</span><span class="token punctuation">,</span> e<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span> <span class="token keyword">finally</span> <span class="token punctuation">&#123;</span>
<span class="token class-name">ErrorContext</span><span class="token punctuation">.</span><span class="token function">instance</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">reset</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">try</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>inputStream <span class="token operator">!=</span> <span class="token keyword">null</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
inputStream<span class="token punctuation">.</span><span class="token function">close</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token punctuation">&#125;</span> <span class="token keyword">catch</span> <span class="token punctuation">(</span><span class="token class-name">IOException</span> e<span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token comment">// Intentionally ignore. Prefer previous error.</span>
<span class="token punctuation">&#125;</span>
<span class="token punctuation">&#125;</span>
<span class="token punctuation">&#125;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>前面也说过，就是解析 <code>mybatis-config.xml</code> 成 <code>Configuration</code></p><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token keyword">public</span> <span class="token class-name">Configuration</span> <span class="token function">parse</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>parsed<span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">throw</span> <span class="token keyword">new</span> <span class="token class-name">BuilderException</span><span class="token punctuation">(</span><span class="token string">"Each XMLConfigBuilder can only be used once."</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
parsed <span class="token operator">=</span> <span class="token boolean">true</span><span class="token punctuation">;</span>
<span class="token function">parseConfiguration</span><span class="token punctuation">(</span>parser<span class="token punctuation">.</span><span class="token function">evalNode</span><span class="token punctuation">(</span><span class="token string">"/configuration"</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">return</span> configuration<span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token keyword">private</span> <span class="token keyword">void</span> <span class="token function">parseConfiguration</span><span class="token punctuation">(</span><span class="token class-name">XNode</span> root<span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">try</span> <span class="token punctuation">&#123;</span>
<span class="token comment">// issue #117 read properties first</span>
<span class="token function">propertiesElement</span><span class="token punctuation">(</span>root<span class="token punctuation">.</span><span class="token function">evalNode</span><span class="token punctuation">(</span><span class="token string">"properties"</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token class-name">Properties</span> settings <span class="token operator">=</span> <span class="token function">settingsAsProperties</span><span class="token punctuation">(</span>root<span class="token punctuation">.</span><span class="token function">evalNode</span><span class="token punctuation">(</span><span class="token string">"settings"</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token function">loadCustomVfs</span><span class="token punctuation">(</span>settings<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token function">loadCustomLogImpl</span><span class="token punctuation">(</span>settings<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token function">typeAliasesElement</span><span class="token punctuation">(</span>root<span class="token punctuation">.</span><span class="token function">evalNode</span><span class="token punctuation">(</span><span class="token string">"typeAliases"</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token function">pluginElement</span><span class="token punctuation">(</span>root<span class="token punctuation">.</span><span class="token function">evalNode</span><span class="token punctuation">(</span><span class="token string">"plugins"</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token function">objectFactoryElement</span><span class="token punctuation">(</span>root<span class="token punctuation">.</span><span class="token function">evalNode</span><span class="token punctuation">(</span><span class="token string">"objectFactory"</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token function">objectWrapperFactoryElement</span><span class="token punctuation">(</span>root<span class="token punctuation">.</span><span class="token function">evalNode</span><span class="token punctuation">(</span><span class="token string">"objectWrapperFactory"</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token function">reflectorFactoryElement</span><span class="token punctuation">(</span>root<span class="token punctuation">.</span><span class="token function">evalNode</span><span class="token punctuation">(</span><span class="token string">"reflectorFactory"</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token function">settingsElement</span><span class="token punctuation">(</span>settings<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token comment">// read it after objectFactory and objectWrapperFactory issue #631</span>
<span class="token comment">// -------------> 是在这里解析了DataSource</span>
<span class="token function">environmentsElement</span><span class="token punctuation">(</span>root<span class="token punctuation">.</span><span class="token function">evalNode</span><span class="token punctuation">(</span><span class="token string">"environments"</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token function">databaseIdProviderElement</span><span class="token punctuation">(</span>root<span class="token punctuation">.</span><span class="token function">evalNode</span><span class="token punctuation">(</span><span class="token string">"databaseIdProvider"</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token function">typeHandlerElement</span><span class="token punctuation">(</span>root<span class="token punctuation">.</span><span class="token function">evalNode</span><span class="token punctuation">(</span><span class="token string">"typeHandlers"</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token function">mapperElement</span><span class="token punctuation">(</span>root<span class="token punctuation">.</span><span class="token function">evalNode</span><span class="token punctuation">(</span><span class="token string">"mappers"</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span> <span class="token keyword">catch</span> <span class="token punctuation">(</span><span class="token class-name">Exception</span> e<span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">throw</span> <span class="token keyword">new</span> <span class="token class-name">BuilderException</span><span class="token punctuation">(</span><span class="token string">"Error parsing SQL Mapper Configuration. Cause: "</span> <span class="token operator">+</span> e<span class="token punctuation">,</span> e<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token punctuation">&#125;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>环境解析了这一块的内容</p><pre class="line-numbers language-markup" data-language="markup"><code class="language-markup"><span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>environments</span> <span class="token attr-name">default</span><span class="token attr-value"><span class="token punctuation attr-equals">=</span><span class="token punctuation">"</span>development<span class="token punctuation">"</span></span><span class="token punctuation">></span></span>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>environment</span> <span class="token attr-name">id</span><span class="token attr-value"><span class="token punctuation attr-equals">=</span><span class="token punctuation">"</span>development<span class="token punctuation">"</span></span><span class="token punctuation">></span></span>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>transactionManager</span> <span class="token attr-name">type</span><span class="token attr-value"><span class="token punctuation attr-equals">=</span><span class="token punctuation">"</span>JDBC<span class="token punctuation">"</span></span><span class="token punctuation">/></span></span>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>dataSource</span> <span class="token attr-name">type</span><span class="token attr-value"><span class="token punctuation attr-equals">=</span><span class="token punctuation">"</span>POOLED<span class="token punctuation">"</span></span><span class="token punctuation">></span></span>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>property</span> <span class="token attr-name">name</span><span class="token attr-value"><span class="token punctuation attr-equals">=</span><span class="token punctuation">"</span>driver<span class="token punctuation">"</span></span> <span class="token attr-name">value</span><span class="token attr-value"><span class="token punctuation attr-equals">=</span><span class="token punctuation">"</span>$&#123;driver&#125;<span class="token punctuation">"</span></span><span class="token punctuation">/></span></span>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>property</span> <span class="token attr-name">name</span><span class="token attr-value"><span class="token punctuation attr-equals">=</span><span class="token punctuation">"</span>url<span class="token punctuation">"</span></span> <span class="token attr-name">value</span><span class="token attr-value"><span class="token punctuation attr-equals">=</span><span class="token punctuation">"</span>$&#123;url&#125;<span class="token punctuation">"</span></span><span class="token punctuation">/></span></span>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>property</span> <span class="token attr-name">name</span><span class="token attr-value"><span class="token punctuation attr-equals">=</span><span class="token punctuation">"</span>username<span class="token punctuation">"</span></span> <span class="token attr-name">value</span><span class="token attr-value"><span class="token punctuation attr-equals">=</span><span class="token punctuation">"</span>$&#123;username&#125;<span class="token punctuation">"</span></span><span class="token punctuation">/></span></span>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>property</span> <span class="token attr-name">name</span><span class="token attr-value"><span class="token punctuation attr-equals">=</span><span class="token punctuation">"</span>password<span class="token punctuation">"</span></span> <span class="token attr-name">value</span><span class="token attr-value"><span class="token punctuation attr-equals">=</span><span class="token punctuation">"</span>$&#123;password&#125;<span class="token punctuation">"</span></span><span class="token punctuation">/></span></span>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>dataSource</span><span class="token punctuation">></span></span>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>environment</span><span class="token punctuation">></span></span>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>environments</span><span class="token punctuation">></span></span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>解析也是自上而下的，</p><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token keyword">private</span> <span class="token keyword">void</span> <span class="token function">environmentsElement</span><span class="token punctuation">(</span><span class="token class-name">XNode</span> context<span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">Exception</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>context <span class="token operator">!=</span> <span class="token keyword">null</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>environment <span class="token operator">==</span> <span class="token keyword">null</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
environment <span class="token operator">=</span> context<span class="token punctuation">.</span><span class="token function">getStringAttribute</span><span class="token punctuation">(</span><span class="token string">"default"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token keyword">for</span> <span class="token punctuation">(</span><span class="token class-name">XNode</span> child <span class="token operator">:</span> context<span class="token punctuation">.</span><span class="token function">getChildren</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token class-name">String</span> id <span class="token operator">=</span> child<span class="token punctuation">.</span><span class="token function">getStringAttribute</span><span class="token punctuation">(</span><span class="token string">"id"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span><span class="token function">isSpecifiedEnvironment</span><span class="token punctuation">(</span>id<span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token class-name">TransactionFactory</span> txFactory <span class="token operator">=</span> <span class="token function">transactionManagerElement</span><span class="token punctuation">(</span>child<span class="token punctuation">.</span><span class="token function">evalNode</span><span class="token punctuation">(</span><span class="token string">"transactionManager"</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token class-name">DataSourceFactory</span> dsFactory <span class="token operator">=</span> <span class="token function">dataSourceElement</span><span class="token punctuation">(</span>child<span class="token punctuation">.</span><span class="token function">evalNode</span><span class="token punctuation">(</span><span class="token string">"dataSource"</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token class-name">DataSource</span> dataSource <span class="token operator">=</span> dsFactory<span class="token punctuation">.</span><span class="token function">getDataSource</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token class-name">Environment<span class="token punctuation">.</span>Builder</span> environmentBuilder <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">Environment<span class="token punctuation">.</span>Builder</span><span class="token punctuation">(</span>id<span class="token punctuation">)</span>
<span class="token punctuation">.</span><span class="token function">transactionFactory</span><span class="token punctuation">(</span>txFactory<span class="token punctuation">)</span>
<span class="token punctuation">.</span><span class="token function">dataSource</span><span class="token punctuation">(</span>dataSource<span class="token punctuation">)</span><span class="token punctuation">;</span>
configuration<span class="token punctuation">.</span><span class="token function">setEnvironment</span><span class="token punctuation">(</span>environmentBuilder<span class="token punctuation">.</span><span class="token function">build</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">break</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token punctuation">&#125;</span>
<span class="token punctuation">&#125;</span>
<span class="token punctuation">&#125;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>前面第一步是解析事务管理器元素</p><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token keyword">private</span> <span class="token class-name">TransactionFactory</span> <span class="token function">transactionManagerElement</span><span class="token punctuation">(</span><span class="token class-name">XNode</span> context<span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">Exception</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>context <span class="token operator">!=</span> <span class="token keyword">null</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token class-name">String</span> type <span class="token operator">=</span> context<span class="token punctuation">.</span><span class="token function">getStringAttribute</span><span class="token punctuation">(</span><span class="token string">"type"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token class-name">Properties</span> props <span class="token operator">=</span> context<span class="token punctuation">.</span><span class="token function">getChildrenAsProperties</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token class-name">TransactionFactory</span> factory <span class="token operator">=</span> <span class="token punctuation">(</span><span class="token class-name">TransactionFactory</span><span class="token punctuation">)</span> <span class="token function">resolveClass</span><span class="token punctuation">(</span>type<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">getDeclaredConstructor</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">newInstance</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
factory<span class="token punctuation">.</span><span class="token function">setProperties</span><span class="token punctuation">(</span>props<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">return</span> factory<span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token keyword">throw</span> <span class="token keyword">new</span> <span class="token class-name">BuilderException</span><span class="token punctuation">(</span><span class="token string">"Environment declaration requires a TransactionFactory."</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>而这里的 <code>resolveClass</code> 其实就使用了上一篇的 <code>typeAliases</code> 系统，这里是使用了 <code>JdbcTransactionFactory</code> 作为事务管理器，<br>后面的就是 <code>DataSourceFactory</code> 的创建也是 <code>DataSource</code> 的创建</p><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token keyword">private</span> <span class="token class-name">DataSourceFactory</span> <span class="token function">dataSourceElement</span><span class="token punctuation">(</span><span class="token class-name">XNode</span> context<span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">Exception</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>context <span class="token operator">!=</span> <span class="token keyword">null</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token class-name">String</span> type <span class="token operator">=</span> context<span class="token punctuation">.</span><span class="token function">getStringAttribute</span><span class="token punctuation">(</span><span class="token string">"type"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token class-name">Properties</span> props <span class="token operator">=</span> context<span class="token punctuation">.</span><span class="token function">getChildrenAsProperties</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token class-name">DataSourceFactory</span> factory <span class="token operator">=</span> <span class="token punctuation">(</span><span class="token class-name">DataSourceFactory</span><span class="token punctuation">)</span> <span class="token function">resolveClass</span><span class="token punctuation">(</span>type<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">getDeclaredConstructor</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">newInstance</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
factory<span class="token punctuation">.</span><span class="token function">setProperties</span><span class="token punctuation">(</span>props<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">return</span> factory<span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token keyword">throw</span> <span class="token keyword">new</span> <span class="token class-name">BuilderException</span><span class="token punctuation">(</span><span class="token string">"Environment declaration requires a DataSourceFactory."</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>因为在config文件中设置了Pooled，所以对应创建的就是 <code>PooledDataSourceFactory</code><br>但是这里其实有个比较需要注意的，mybatis 这里的其实是继承了 <code>UnpooledDataSourceFactory</code><br>将基础方法都放在了 <code>UnpooledDataSourceFactory</code> 中</p><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token keyword">public</span> <span class="token keyword">class</span> <span class="token class-name">PooledDataSourceFactory</span> <span class="token keyword">extends</span> <span class="token class-name">UnpooledDataSourceFactory</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">public</span> <span class="token class-name">PooledDataSourceFactory</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">this</span><span class="token punctuation">.</span>dataSource <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">PooledDataSource</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token punctuation">&#125;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>这里只保留了在构造方法里创建 <code>DataSource</code><br>而这个 <code>PooledDataSource</code> 虽然没有直接继承 <code>UnpooledDataSource</code>，但其实<br>在构造方法里也是</p><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token keyword">public</span> <span class="token class-name">PooledDataSource</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
dataSource <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">UnpooledDataSource</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span></span></code></pre><p>至于为什么这么做呢应该也是考虑到能比较多的复用代码，因为 <code>Pooled</code> 其实跟 <code>Unpooled</code> 最重要的差别就在于是不是每次都重开连接<br>使用连接池能够让应用在有大量查询的时候不用反复创建连接，省去了建联的网络等开销，<code>Unpooled</code>就是完成与数据库的连接，并可以获取该连接<br>主要的代码</p><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token annotation punctuation">@Override</span>
<span class="token keyword">public</span> <span class="token class-name">Connection</span> <span class="token function">getConnection</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">SQLException</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">return</span> <span class="token function">doGetConnection</span><span class="token punctuation">(</span>username<span class="token punctuation">,</span> password<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token annotation punctuation">@Override</span>
<span class="token keyword">public</span> <span class="token class-name">Connection</span> <span class="token function">getConnection</span><span class="token punctuation">(</span><span class="token class-name">String</span> username<span class="token punctuation">,</span> <span class="token class-name">String</span> password<span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">SQLException</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">return</span> <span class="token function">doGetConnection</span><span class="token punctuation">(</span>username<span class="token punctuation">,</span> password<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token keyword">private</span> <span class="token class-name">Connection</span> <span class="token function">doGetConnection</span><span class="token punctuation">(</span><span class="token class-name">String</span> username<span class="token punctuation">,</span> <span class="token class-name">String</span> password<span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">SQLException</span> <span class="token punctuation">&#123;</span>
<span class="token class-name">Properties</span> props <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">Properties</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>driverProperties <span class="token operator">!=</span> <span class="token keyword">null</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
props<span class="token punctuation">.</span><span class="token function">putAll</span><span class="token punctuation">(</span>driverProperties<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>username <span class="token operator">!=</span> <span class="token keyword">null</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
props<span class="token punctuation">.</span><span class="token function">setProperty</span><span class="token punctuation">(</span><span class="token string">"user"</span><span class="token punctuation">,</span> username<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>password <span class="token operator">!=</span> <span class="token keyword">null</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
props<span class="token punctuation">.</span><span class="token function">setProperty</span><span class="token punctuation">(</span><span class="token string">"password"</span><span class="token punctuation">,</span> password<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token keyword">return</span> <span class="token function">doGetConnection</span><span class="token punctuation">(</span>props<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token keyword">private</span> <span class="token class-name">Connection</span> <span class="token function">doGetConnection</span><span class="token punctuation">(</span><span class="token class-name">Properties</span> properties<span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">SQLException</span> <span class="token punctuation">&#123;</span>
<span class="token function">initializeDriver</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token class-name">Connection</span> connection <span class="token operator">=</span> <span class="token class-name">DriverManager</span><span class="token punctuation">.</span><span class="token function">getConnection</span><span class="token punctuation">(</span>url<span class="token punctuation">,</span> properties<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token function">configureConnection</span><span class="token punctuation">(</span>connection<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">return</span> connection<span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>而对于Pooled就会处理池化的逻辑</p><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token keyword">private</span> <span class="token class-name">PooledConnection</span> <span class="token function">popConnection</span><span class="token punctuation">(</span><span class="token class-name">String</span> username<span class="token punctuation">,</span> <span class="token class-name">String</span> password<span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">SQLException</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">boolean</span> countedWait <span class="token operator">=</span> <span class="token boolean">false</span><span class="token punctuation">;</span>
<span class="token class-name">PooledConnection</span> conn <span class="token operator">=</span> <span class="token keyword">null</span><span class="token punctuation">;</span>
<span class="token keyword">long</span> t <span class="token operator">=</span> <span class="token class-name">System</span><span class="token punctuation">.</span><span class="token function">currentTimeMillis</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">int</span> localBadConnectionCount <span class="token operator">=</span> <span class="token number">0</span><span class="token punctuation">;</span>
<span class="token keyword">while</span> <span class="token punctuation">(</span>conn <span class="token operator">==</span> <span class="token keyword">null</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
lock<span class="token punctuation">.</span><span class="token function">lock</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">try</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span><span class="token operator">!</span>state<span class="token punctuation">.</span>idleConnections<span class="token punctuation">.</span><span class="token function">isEmpty</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token comment">// Pool has available connection</span>
conn <span class="token operator">=</span> state<span class="token punctuation">.</span>idleConnections<span class="token punctuation">.</span><span class="token function">remove</span><span class="token punctuation">(</span><span class="token number">0</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>log<span class="token punctuation">.</span><span class="token function">isDebugEnabled</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
log<span class="token punctuation">.</span><span class="token function">debug</span><span class="token punctuation">(</span><span class="token string">"Checked out connection "</span> <span class="token operator">+</span> conn<span class="token punctuation">.</span><span class="token function">getRealHashCode</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator">+</span> <span class="token string">" from pool."</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token punctuation">&#125;</span> <span class="token keyword">else</span> <span class="token punctuation">&#123;</span>
<span class="token comment">// Pool does not have available connection</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>state<span class="token punctuation">.</span>activeConnections<span class="token punctuation">.</span><span class="token function">size</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator">&lt;</span> poolMaximumActiveConnections<span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token comment">// Can create new connection</span>
conn <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">PooledConnection</span><span class="token punctuation">(</span>dataSource<span class="token punctuation">.</span><span class="token function">getConnection</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">,</span> <span class="token keyword">this</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>log<span class="token punctuation">.</span><span class="token function">isDebugEnabled</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
log<span class="token punctuation">.</span><span class="token function">debug</span><span class="token punctuation">(</span><span class="token string">"Created connection "</span> <span class="token operator">+</span> conn<span class="token punctuation">.</span><span class="token function">getRealHashCode</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator">+</span> <span class="token string">"."</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token punctuation">&#125;</span> <span class="token keyword">else</span> <span class="token punctuation">&#123;</span>
<span class="token comment">// Cannot create new connection</span>
<span class="token class-name">PooledConnection</span> oldestActiveConnection <span class="token operator">=</span> state<span class="token punctuation">.</span>activeConnections<span class="token punctuation">.</span><span class="token function">get</span><span class="token punctuation">(</span><span class="token number">0</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">long</span> longestCheckoutTime <span class="token operator">=</span> oldestActiveConnection<span class="token punctuation">.</span><span class="token function">getCheckoutTime</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>longestCheckoutTime <span class="token operator">></span> poolMaximumCheckoutTime<span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token comment">// Can claim overdue connection</span>
state<span class="token punctuation">.</span>claimedOverdueConnectionCount<span class="token operator">++</span><span class="token punctuation">;</span>
state<span class="token punctuation">.</span>accumulatedCheckoutTimeOfOverdueConnections <span class="token operator">+=</span> longestCheckoutTime<span class="token punctuation">;</span>
state<span class="token punctuation">.</span>accumulatedCheckoutTime <span class="token operator">+=</span> longestCheckoutTime<span class="token punctuation">;</span>
state<span class="token punctuation">.</span>activeConnections<span class="token punctuation">.</span><span class="token function">remove</span><span class="token punctuation">(</span>oldestActiveConnection<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span><span class="token operator">!</span>oldestActiveConnection<span class="token punctuation">.</span><span class="token function">getRealConnection</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">getAutoCommit</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">try</span> <span class="token punctuation">&#123;</span>
oldestActiveConnection<span class="token punctuation">.</span><span class="token function">getRealConnection</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">rollback</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span> <span class="token keyword">catch</span> <span class="token punctuation">(</span><span class="token class-name">SQLException</span> e<span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token comment">/*
Just log a message for debug and continue to execute the following
statement like nothing happened.
Wrap the bad connection with a new PooledConnection, this will help
to not interrupt current executing thread and give current thread a
chance to join the next competition for another valid/good database
connection. At the end of this loop, bad &#123;@link @conn&#125; will be set as null.
*/</span>
log<span class="token punctuation">.</span><span class="token function">debug</span><span class="token punctuation">(</span><span class="token string">"Bad connection. Could not roll back"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token punctuation">&#125;</span>
conn <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">PooledConnection</span><span class="token punctuation">(</span>oldestActiveConnection<span class="token punctuation">.</span><span class="token function">getRealConnection</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">,</span> <span class="token keyword">this</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
conn<span class="token punctuation">.</span><span class="token function">setCreatedTimestamp</span><span class="token punctuation">(</span>oldestActiveConnection<span class="token punctuation">.</span><span class="token function">getCreatedTimestamp</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
conn<span class="token punctuation">.</span><span class="token function">setLastUsedTimestamp</span><span class="token punctuation">(</span>oldestActiveConnection<span class="token punctuation">.</span><span class="token function">getLastUsedTimestamp</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
oldestActiveConnection<span class="token punctuation">.</span><span class="token function">invalidate</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>log<span class="token punctuation">.</span><span class="token function">isDebugEnabled</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
log<span class="token punctuation">.</span><span class="token function">debug</span><span class="token punctuation">(</span><span class="token string">"Claimed overdue connection "</span> <span class="token operator">+</span> conn<span class="token punctuation">.</span><span class="token function">getRealHashCode</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator">+</span> <span class="token string">"."</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token punctuation">&#125;</span> <span class="token keyword">else</span> <span class="token punctuation">&#123;</span>
<span class="token comment">// Must wait</span>
<span class="token keyword">try</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span><span class="token operator">!</span>countedWait<span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
state<span class="token punctuation">.</span>hadToWaitCount<span class="token operator">++</span><span class="token punctuation">;</span>
countedWait <span class="token operator">=</span> <span class="token boolean">true</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>log<span class="token punctuation">.</span><span class="token function">isDebugEnabled</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
log<span class="token punctuation">.</span><span class="token function">debug</span><span class="token punctuation">(</span><span class="token string">"Waiting as long as "</span> <span class="token operator">+</span> poolTimeToWait <span class="token operator">+</span> <span class="token string">" milliseconds for connection."</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token keyword">long</span> wt <span class="token operator">=</span> <span class="token class-name">System</span><span class="token punctuation">.</span><span class="token function">currentTimeMillis</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
condition<span class="token punctuation">.</span><span class="token function">await</span><span class="token punctuation">(</span>poolTimeToWait<span class="token punctuation">,</span> <span class="token class-name">TimeUnit</span><span class="token punctuation">.</span><span class="token constant">MILLISECONDS</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
state<span class="token punctuation">.</span>accumulatedWaitTime <span class="token operator">+=</span> <span class="token class-name">System</span><span class="token punctuation">.</span><span class="token function">currentTimeMillis</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator">-</span> wt<span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span> <span class="token keyword">catch</span> <span class="token punctuation">(</span><span class="token class-name">InterruptedException</span> e<span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token comment">// set interrupt flag</span>
<span class="token class-name">Thread</span><span class="token punctuation">.</span><span class="token function">currentThread</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">interrupt</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">break</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token punctuation">&#125;</span>
<span class="token punctuation">&#125;</span>
<span class="token punctuation">&#125;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>conn <span class="token operator">!=</span> <span class="token keyword">null</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token comment">// ping to server and check the connection is valid or not</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>conn<span class="token punctuation">.</span><span class="token function">isValid</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span><span class="token operator">!</span>conn<span class="token punctuation">.</span><span class="token function">getRealConnection</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">getAutoCommit</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
conn<span class="token punctuation">.</span><span class="token function">getRealConnection</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">rollback</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
conn<span class="token punctuation">.</span><span class="token function">setConnectionTypeCode</span><span class="token punctuation">(</span><span class="token function">assembleConnectionTypeCode</span><span class="token punctuation">(</span>dataSource<span class="token punctuation">.</span><span class="token function">getUrl</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">,</span> username<span class="token punctuation">,</span> password<span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
conn<span class="token punctuation">.</span><span class="token function">setCheckoutTimestamp</span><span class="token punctuation">(</span><span class="token class-name">System</span><span class="token punctuation">.</span><span class="token function">currentTimeMillis</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
conn<span class="token punctuation">.</span><span class="token function">setLastUsedTimestamp</span><span class="token punctuation">(</span><span class="token class-name">System</span><span class="token punctuation">.</span><span class="token function">currentTimeMillis</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
state<span class="token punctuation">.</span>activeConnections<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span>conn<span class="token punctuation">)</span><span class="token punctuation">;</span>
state<span class="token punctuation">.</span>requestCount<span class="token operator">++</span><span class="token punctuation">;</span>
state<span class="token punctuation">.</span>accumulatedRequestTime <span class="token operator">+=</span> <span class="token class-name">System</span><span class="token punctuation">.</span><span class="token function">currentTimeMillis</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator">-</span> t<span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span> <span class="token keyword">else</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>log<span class="token punctuation">.</span><span class="token function">isDebugEnabled</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
log<span class="token punctuation">.</span><span class="token function">debug</span><span class="token punctuation">(</span><span class="token string">"A bad connection ("</span> <span class="token operator">+</span> conn<span class="token punctuation">.</span><span class="token function">getRealHashCode</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator">+</span> <span class="token string">") was returned from the pool, getting another connection."</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
state<span class="token punctuation">.</span>badConnectionCount<span class="token operator">++</span><span class="token punctuation">;</span>
localBadConnectionCount<span class="token operator">++</span><span class="token punctuation">;</span>
conn <span class="token operator">=</span> <span class="token keyword">null</span><span class="token punctuation">;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>localBadConnectionCount <span class="token operator">></span> <span class="token punctuation">(</span>poolMaximumIdleConnections <span class="token operator">+</span> poolMaximumLocalBadConnectionTolerance<span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>log<span class="token punctuation">.</span><span class="token function">isDebugEnabled</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
log<span class="token punctuation">.</span><span class="token function">debug</span><span class="token punctuation">(</span><span class="token string">"PooledDataSource: Could not get a good connection to the database."</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token keyword">throw</span> <span class="token keyword">new</span> <span class="token class-name">SQLException</span><span class="token punctuation">(</span><span class="token string">"PooledDataSource: Could not get a good connection to the database."</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token punctuation">&#125;</span>
<span class="token punctuation">&#125;</span>
<span class="token punctuation">&#125;</span> <span class="token keyword">finally</span> <span class="token punctuation">&#123;</span>
lock<span class="token punctuation">.</span><span class="token function">unlock</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token punctuation">&#125;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>conn <span class="token operator">==</span> <span class="token keyword">null</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>log<span class="token punctuation">.</span><span class="token function">isDebugEnabled</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
log<span class="token punctuation">.</span><span class="token function">debug</span><span class="token punctuation">(</span><span class="token string">"PooledDataSource: Unknown severe error condition. The connection pool returned a null connection."</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token keyword">throw</span> <span class="token keyword">new</span> <span class="token class-name">SQLException</span><span class="token punctuation">(</span><span class="token string">"PooledDataSource: Unknown severe error condition. The connection pool returned a null connection."</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token keyword">return</span> conn<span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>它的入口不是个get方法，而是pop，从含义来来讲就不一样<br><code>org.apache.ibatis.datasource.pooled.PooledDataSource#getConnection()</code></p><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token annotation punctuation">@Override</span>
<span class="token keyword">public</span> <span class="token class-name">Connection</span> <span class="token function">getConnection</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">SQLException</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">return</span> <span class="token function">popConnection</span><span class="token punctuation">(</span>dataSource<span class="token punctuation">.</span><span class="token function">getUsername</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">,</span> dataSource<span class="token punctuation">.</span><span class="token function">getPassword</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">getProxyConnection</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span></span></code></pre><p>对于具体怎么获取连接我们可以下一篇具体讲下</p></div><footer class="post-footer"><div class="post-eof"></div></footer></article></div><div class="post-block"><article itemscope itemtype="http://schema.org/Article" class="post-content"><link itemprop="mainEntityOfPage" href="https://nicksxs.me/2023/01/01/mybatis%E7%B3%BB%E5%88%97-typeAliases%E7%B3%BB%E7%BB%9F/"><span hidden itemprop="author" itemscope itemtype="http://schema.org/Person"><meta itemprop="image" content="/uploads/avatar.jpg"><meta itemprop="name" content="Nicksxs"></span><span hidden itemprop="publisher" itemscope itemtype="http://schema.org/Organization"><meta itemprop="name" content="Nicksxs's Blog"><meta itemprop="description" content="learn from zero,技术博客，Nicksxs，史学森"></span><span hidden itemprop="post" itemscope itemtype="http://schema.org/CreativeWork"><meta itemprop="name" content="undefined | Nicksxs's Blog"><meta itemprop="description" content=""></span><header class="post-header"><h2 class="post-title" itemprop="name headline"><a href="/2023/01/01/mybatis%E7%B3%BB%E5%88%97-typeAliases%E7%B3%BB%E7%BB%9F/" class="post-title-link" itemprop="url">mybatis系列-typeAliases系统</a></h2><div class="post-meta-container"><div class="post-meta"><span class="post-meta-item"><span class="post-meta-item-icon"><i class="far fa-calendar"></i> </span><span class="post-meta-item-text">发表于</span> <time title="创建时间：2023-01-01 20:07:42 / 修改时间：20:08:24" itemprop="dateCreated datePublished" datetime="2023-01-01T20:07:42+08:00">2023-01-01</time> </span><span class="post-meta-item"><span class="post-meta-item-icon"><i class="far fa-folder"></i> </span><span class="post-meta-item-text">分类于</span> <span itemprop="about" itemscope itemtype="http://schema.org/Thing"><a href="/categories/Java/" itemprop="url" rel="index"><span itemprop="name">Java</span></a> </span>， <span itemprop="about" itemscope itemtype="http://schema.org/Thing"><a href="/categories/Java/Mybatis/" itemprop="url" rel="index"><span itemprop="name">Mybatis</span></a> </span></span><span id="/2023/01/01/mybatis%E7%B3%BB%E5%88%97-typeAliases%E7%B3%BB%E7%BB%9F/" class="post-meta-item leancloud_visitors" data-flag-title="mybatis系列-typeAliases系统" title="阅读次数"><span class="post-meta-item-icon"><i class="far fa-eye"></i> </span><span class="post-meta-item-text">阅读次数：</span> <span class="leancloud-visitors-count"></span> </span><span class="post-meta-item"><span class="post-meta-item-icon"><i class="far fa-comment"></i> </span><span class="post-meta-item-text">Disqus：</span> <a title="disqus" href="/2023/01/01/mybatis%E7%B3%BB%E5%88%97-typeAliases%E7%B3%BB%E7%BB%9F/#disqus_thread" itemprop="discussionUrl"><span class="post-comments-count disqus-comment-count" data-disqus-identifier="2023/01/01/mybatis系列-typeAliases系统/" itemprop="commentCount"></span></a></span></div></div></header><div class="post-body" itemprop="articleBody"><p>其实前面已经聊到过这个概念，在mybatis的配置中，以及一些初始化逻辑都是用了typeAliases，</p><pre class="line-numbers language-markup" data-language="markup"><code class="language-markup"><span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>typeAliases</span><span class="token punctuation">></span></span>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>typeAlias</span> <span class="token attr-name">alias</span><span class="token attr-value"><span class="token punctuation attr-equals">=</span><span class="token punctuation">"</span>Author<span class="token punctuation">"</span></span> <span class="token attr-name">type</span><span class="token attr-value"><span class="token punctuation attr-equals">=</span><span class="token punctuation">"</span>domain.blog.Author<span class="token punctuation">"</span></span><span class="token punctuation">/></span></span>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>typeAlias</span> <span class="token attr-name">alias</span><span class="token attr-value"><span class="token punctuation attr-equals">=</span><span class="token punctuation">"</span>Blog<span class="token punctuation">"</span></span> <span class="token attr-name">type</span><span class="token attr-value"><span class="token punctuation attr-equals">=</span><span class="token punctuation">"</span>domain.blog.Blog<span class="token punctuation">"</span></span><span class="token punctuation">/></span></span>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>typeAlias</span> <span class="token attr-name">alias</span><span class="token attr-value"><span class="token punctuation attr-equals">=</span><span class="token punctuation">"</span>Comment<span class="token punctuation">"</span></span> <span class="token attr-name">type</span><span class="token attr-value"><span class="token punctuation attr-equals">=</span><span class="token punctuation">"</span>domain.blog.Comment<span class="token punctuation">"</span></span><span class="token punctuation">/></span></span>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>typeAlias</span> <span class="token attr-name">alias</span><span class="token attr-value"><span class="token punctuation attr-equals">=</span><span class="token punctuation">"</span>Post<span class="token punctuation">"</span></span> <span class="token attr-name">type</span><span class="token attr-value"><span class="token punctuation attr-equals">=</span><span class="token punctuation">"</span>domain.blog.Post<span class="token punctuation">"</span></span><span class="token punctuation">/></span></span>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>typeAlias</span> <span class="token attr-name">alias</span><span class="token attr-value"><span class="token punctuation attr-equals">=</span><span class="token punctuation">"</span>Section<span class="token punctuation">"</span></span> <span class="token attr-name">type</span><span class="token attr-value"><span class="token punctuation attr-equals">=</span><span class="token punctuation">"</span>domain.blog.Section<span class="token punctuation">"</span></span><span class="token punctuation">/></span></span>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>typeAlias</span> <span class="token attr-name">alias</span><span class="token attr-value"><span class="token punctuation attr-equals">=</span><span class="token punctuation">"</span>Tag<span class="token punctuation">"</span></span> <span class="token attr-name">type</span><span class="token attr-value"><span class="token punctuation attr-equals">=</span><span class="token punctuation">"</span>domain.blog.Tag<span class="token punctuation">"</span></span><span class="token punctuation">/></span></span>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>typeAliases</span><span class="token punctuation">></span></span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>可以在这里注册类型别名，然后在mybatis中配置使用时，可以简化这些类型的使用，其底层逻辑主要是一个map，</p><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token keyword">public</span> <span class="token keyword">class</span> <span class="token class-name">TypeAliasRegistry</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">private</span> <span class="token keyword">final</span> <span class="token class-name">Map</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">String</span><span class="token punctuation">,</span> <span class="token class-name">Class</span><span class="token punctuation">&lt;</span><span class="token operator">?</span><span class="token punctuation">></span><span class="token punctuation">></span></span> typeAliases <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">HashMap</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token punctuation">></span></span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span></span></code></pre><p>以string作为key，class对象作为value，比如我们在一开始使用的配置文件</p><pre class="line-numbers language-markup" data-language="markup"><code class="language-markup"><span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>dataSource</span> <span class="token attr-name">type</span><span class="token attr-value"><span class="token punctuation attr-equals">=</span><span class="token punctuation">"</span>POOLED<span class="token punctuation">"</span></span><span class="token punctuation">></span></span>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>property</span> <span class="token attr-name">name</span><span class="token attr-value"><span class="token punctuation attr-equals">=</span><span class="token punctuation">"</span>driver<span class="token punctuation">"</span></span> <span class="token attr-name">value</span><span class="token attr-value"><span class="token punctuation attr-equals">=</span><span class="token punctuation">"</span>$&#123;driver&#125;<span class="token punctuation">"</span></span><span class="token punctuation">/></span></span>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>property</span> <span class="token attr-name">name</span><span class="token attr-value"><span class="token punctuation attr-equals">=</span><span class="token punctuation">"</span>url<span class="token punctuation">"</span></span> <span class="token attr-name">value</span><span class="token attr-value"><span class="token punctuation attr-equals">=</span><span class="token punctuation">"</span>$&#123;url&#125;<span class="token punctuation">"</span></span><span class="token punctuation">/></span></span>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>property</span> <span class="token attr-name">name</span><span class="token attr-value"><span class="token punctuation attr-equals">=</span><span class="token punctuation">"</span>username<span class="token punctuation">"</span></span> <span class="token attr-name">value</span><span class="token attr-value"><span class="token punctuation attr-equals">=</span><span class="token punctuation">"</span>$&#123;username&#125;<span class="token punctuation">"</span></span><span class="token punctuation">/></span></span>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>property</span> <span class="token attr-name">name</span><span class="token attr-value"><span class="token punctuation attr-equals">=</span><span class="token punctuation">"</span>password<span class="token punctuation">"</span></span> <span class="token attr-name">value</span><span class="token attr-value"><span class="token punctuation attr-equals">=</span><span class="token punctuation">"</span>$&#123;password&#125;<span class="token punctuation">"</span></span><span class="token punctuation">/></span></span>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>dataSource</span><span class="token punctuation">></span></span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>这里使用的dataSource是POOLED，那它肯定是个别名或者需要对应处理<br>而这个别名就是在Configuration的构造方法里初始化</p><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token keyword">public</span> <span class="token class-name">Configuration</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
typeAliasRegistry<span class="token punctuation">.</span><span class="token function">registerAlias</span><span class="token punctuation">(</span><span class="token string">"JDBC"</span><span class="token punctuation">,</span> <span class="token class-name">JdbcTransactionFactory</span><span class="token punctuation">.</span><span class="token keyword">class</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
typeAliasRegistry<span class="token punctuation">.</span><span class="token function">registerAlias</span><span class="token punctuation">(</span><span class="token string">"MANAGED"</span><span class="token punctuation">,</span> <span class="token class-name">ManagedTransactionFactory</span><span class="token punctuation">.</span><span class="token keyword">class</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
typeAliasRegistry<span class="token punctuation">.</span><span class="token function">registerAlias</span><span class="token punctuation">(</span><span class="token string">"JNDI"</span><span class="token punctuation">,</span> <span class="token class-name">JndiDataSourceFactory</span><span class="token punctuation">.</span><span class="token keyword">class</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
typeAliasRegistry<span class="token punctuation">.</span><span class="token function">registerAlias</span><span class="token punctuation">(</span><span class="token string">"POOLED"</span><span class="token punctuation">,</span> <span class="token class-name">PooledDataSourceFactory</span><span class="token punctuation">.</span><span class="token keyword">class</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
typeAliasRegistry<span class="token punctuation">.</span><span class="token function">registerAlias</span><span class="token punctuation">(</span><span class="token string">"UNPOOLED"</span><span class="token punctuation">,</span> <span class="token class-name">UnpooledDataSourceFactory</span><span class="token punctuation">.</span><span class="token keyword">class</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
typeAliasRegistry<span class="token punctuation">.</span><span class="token function">registerAlias</span><span class="token punctuation">(</span><span class="token string">"PERPETUAL"</span><span class="token punctuation">,</span> <span class="token class-name">PerpetualCache</span><span class="token punctuation">.</span><span class="token keyword">class</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
typeAliasRegistry<span class="token punctuation">.</span><span class="token function">registerAlias</span><span class="token punctuation">(</span><span class="token string">"FIFO"</span><span class="token punctuation">,</span> <span class="token class-name">FifoCache</span><span class="token punctuation">.</span><span class="token keyword">class</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
typeAliasRegistry<span class="token punctuation">.</span><span class="token function">registerAlias</span><span class="token punctuation">(</span><span class="token string">"LRU"</span><span class="token punctuation">,</span> <span class="token class-name">LruCache</span><span class="token punctuation">.</span><span class="token keyword">class</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
typeAliasRegistry<span class="token punctuation">.</span><span class="token function">registerAlias</span><span class="token punctuation">(</span><span class="token string">"SOFT"</span><span class="token punctuation">,</span> <span class="token class-name">SoftCache</span><span class="token punctuation">.</span><span class="token keyword">class</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
typeAliasRegistry<span class="token punctuation">.</span><span class="token function">registerAlias</span><span class="token punctuation">(</span><span class="token string">"WEAK"</span><span class="token punctuation">,</span> <span class="token class-name">WeakCache</span><span class="token punctuation">.</span><span class="token keyword">class</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
typeAliasRegistry<span class="token punctuation">.</span><span class="token function">registerAlias</span><span class="token punctuation">(</span><span class="token string">"DB_VENDOR"</span><span class="token punctuation">,</span> <span class="token class-name">VendorDatabaseIdProvider</span><span class="token punctuation">.</span><span class="token keyword">class</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
typeAliasRegistry<span class="token punctuation">.</span><span class="token function">registerAlias</span><span class="token punctuation">(</span><span class="token string">"XML"</span><span class="token punctuation">,</span> <span class="token class-name">XMLLanguageDriver</span><span class="token punctuation">.</span><span class="token keyword">class</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
typeAliasRegistry<span class="token punctuation">.</span><span class="token function">registerAlias</span><span class="token punctuation">(</span><span class="token string">"RAW"</span><span class="token punctuation">,</span> <span class="token class-name">RawLanguageDriver</span><span class="token punctuation">.</span><span class="token keyword">class</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
typeAliasRegistry<span class="token punctuation">.</span><span class="token function">registerAlias</span><span class="token punctuation">(</span><span class="token string">"SLF4J"</span><span class="token punctuation">,</span> <span class="token class-name">Slf4jImpl</span><span class="token punctuation">.</span><span class="token keyword">class</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
typeAliasRegistry<span class="token punctuation">.</span><span class="token function">registerAlias</span><span class="token punctuation">(</span><span class="token string">"COMMONS_LOGGING"</span><span class="token punctuation">,</span> <span class="token class-name">JakartaCommonsLoggingImpl</span><span class="token punctuation">.</span><span class="token keyword">class</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
typeAliasRegistry<span class="token punctuation">.</span><span class="token function">registerAlias</span><span class="token punctuation">(</span><span class="token string">"LOG4J"</span><span class="token punctuation">,</span> <span class="token class-name">Log4jImpl</span><span class="token punctuation">.</span><span class="token keyword">class</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
typeAliasRegistry<span class="token punctuation">.</span><span class="token function">registerAlias</span><span class="token punctuation">(</span><span class="token string">"LOG4J2"</span><span class="token punctuation">,</span> <span class="token class-name">Log4j2Impl</span><span class="token punctuation">.</span><span class="token keyword">class</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
typeAliasRegistry<span class="token punctuation">.</span><span class="token function">registerAlias</span><span class="token punctuation">(</span><span class="token string">"JDK_LOGGING"</span><span class="token punctuation">,</span> <span class="token class-name">Jdk14LoggingImpl</span><span class="token punctuation">.</span><span class="token keyword">class</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
typeAliasRegistry<span class="token punctuation">.</span><span class="token function">registerAlias</span><span class="token punctuation">(</span><span class="token string">"STDOUT_LOGGING"</span><span class="token punctuation">,</span> <span class="token class-name">StdOutImpl</span><span class="token punctuation">.</span><span class="token keyword">class</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
typeAliasRegistry<span class="token punctuation">.</span><span class="token function">registerAlias</span><span class="token punctuation">(</span><span class="token string">"NO_LOGGING"</span><span class="token punctuation">,</span> <span class="token class-name">NoLoggingImpl</span><span class="token punctuation">.</span><span class="token keyword">class</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
typeAliasRegistry<span class="token punctuation">.</span><span class="token function">registerAlias</span><span class="token punctuation">(</span><span class="token string">"CGLIB"</span><span class="token punctuation">,</span> <span class="token class-name">CglibProxyFactory</span><span class="token punctuation">.</span><span class="token keyword">class</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
typeAliasRegistry<span class="token punctuation">.</span><span class="token function">registerAlias</span><span class="token punctuation">(</span><span class="token string">"JAVASSIST"</span><span class="token punctuation">,</span> <span class="token class-name">JavassistProxyFactory</span><span class="token punctuation">.</span><span class="token keyword">class</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
languageRegistry<span class="token punctuation">.</span><span class="token function">setDefaultDriverClass</span><span class="token punctuation">(</span><span class="token class-name">XMLLanguageDriver</span><span class="token punctuation">.</span><span class="token keyword">class</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
languageRegistry<span class="token punctuation">.</span><span class="token function">register</span><span class="token punctuation">(</span><span class="token class-name">RawLanguageDriver</span><span class="token punctuation">.</span><span class="token keyword">class</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>正是通过<code>typeAliasRegistry.registerAlias(&quot;POOLED&quot;, PooledDataSourceFactory.class);</code>这一行，注册了<br><code>POOLED</code>对应的别名类型是<code>PooledDataSourceFactory.class</code><br>具体的注册方法是在</p><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">registerAlias</span><span class="token punctuation">(</span><span class="token class-name">String</span> alias<span class="token punctuation">,</span> <span class="token class-name">Class</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token operator">?</span><span class="token punctuation">></span></span> value<span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>alias <span class="token operator">==</span> <span class="token keyword">null</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">throw</span> <span class="token keyword">new</span> <span class="token class-name">TypeException</span><span class="token punctuation">(</span><span class="token string">"The parameter alias cannot be null"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token comment">// issue #748</span>
<span class="token comment">// 转换成小写，</span>
<span class="token class-name">String</span> key <span class="token operator">=</span> alias<span class="token punctuation">.</span><span class="token function">toLowerCase</span><span class="token punctuation">(</span><span class="token class-name">Locale</span><span class="token punctuation">.</span><span class="token constant">ENGLISH</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token comment">// 判断是否已经注册过了</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>typeAliases<span class="token punctuation">.</span><span class="token function">containsKey</span><span class="token punctuation">(</span>key<span class="token punctuation">)</span> <span class="token operator">&amp;&amp;</span> typeAliases<span class="token punctuation">.</span><span class="token function">get</span><span class="token punctuation">(</span>key<span class="token punctuation">)</span> <span class="token operator">!=</span> <span class="token keyword">null</span> <span class="token operator">&amp;&amp;</span> <span class="token operator">!</span>typeAliases<span class="token punctuation">.</span><span class="token function">get</span><span class="token punctuation">(</span>key<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">equals</span><span class="token punctuation">(</span>value<span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">throw</span> <span class="token keyword">new</span> <span class="token class-name">TypeException</span><span class="token punctuation">(</span><span class="token string">"The alias '"</span> <span class="token operator">+</span> alias <span class="token operator">+</span> <span class="token string">"' is already mapped to the value '"</span> <span class="token operator">+</span> typeAliases<span class="token punctuation">.</span><span class="token function">get</span><span class="token punctuation">(</span>key<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">getName</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator">+</span> <span class="token string">"'."</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token comment">// 放进map里</span>
typeAliases<span class="token punctuation">.</span><span class="token function">put</span><span class="token punctuation">(</span>key<span class="token punctuation">,</span> value<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>而获取的逻辑在这</p><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token keyword">public</span> <span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">T</span><span class="token punctuation">></span></span> <span class="token class-name">Class</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">T</span><span class="token punctuation">></span></span> <span class="token function">resolveAlias</span><span class="token punctuation">(</span><span class="token class-name">String</span> string<span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">try</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>string <span class="token operator">==</span> <span class="token keyword">null</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">return</span> <span class="token keyword">null</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token comment">// issue #748</span>
<span class="token comment">// 同样的转成小写</span>
<span class="token class-name">String</span> key <span class="token operator">=</span> string<span class="token punctuation">.</span><span class="token function">toLowerCase</span><span class="token punctuation">(</span><span class="token class-name">Locale</span><span class="token punctuation">.</span><span class="token constant">ENGLISH</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token class-name">Class</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">T</span><span class="token punctuation">></span></span> value<span class="token punctuation">;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>typeAliases<span class="token punctuation">.</span><span class="token function">containsKey</span><span class="token punctuation">(</span>key<span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
value <span class="token operator">=</span> <span class="token punctuation">(</span><span class="token class-name">Class</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">T</span><span class="token punctuation">></span></span><span class="token punctuation">)</span> typeAliases<span class="token punctuation">.</span><span class="token function">get</span><span class="token punctuation">(</span>key<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span> <span class="token keyword">else</span> <span class="token punctuation">&#123;</span>
<span class="token comment">// 这里还有从路径下处理的逻辑</span>
value <span class="token operator">=</span> <span class="token punctuation">(</span><span class="token class-name">Class</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">T</span><span class="token punctuation">></span></span><span class="token punctuation">)</span> <span class="token class-name">Resources</span><span class="token punctuation">.</span><span class="token function">classForName</span><span class="token punctuation">(</span>string<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token keyword">return</span> value<span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span> <span class="token keyword">catch</span> <span class="token punctuation">(</span><span class="token class-name">ClassNotFoundException</span> e<span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">throw</span> <span class="token keyword">new</span> <span class="token class-name">TypeException</span><span class="token punctuation">(</span><span class="token string">"Could not resolve type alias '"</span> <span class="token operator">+</span> string <span class="token operator">+</span> <span class="token string">"'. Cause: "</span> <span class="token operator">+</span> e<span class="token punctuation">,</span> e<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token punctuation">&#125;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>逻辑比较简单，但是在mybatis中也是不可或缺的一块概念</p></div><footer class="post-footer"><div class="post-eof"></div></footer></article></div><div class="post-block"><article itemscope itemtype="http://schema.org/Article" class="post-content"><link itemprop="mainEntityOfPage" href="https://nicksxs.me/2022/12/25/docker%E6%AF%94%E4%B8%80%E8%88%AC%E5%A4%9A%E4%B8%80%E7%82%B9%E7%9A%84%E5%88%9D%E5%AD%A6%E8%80%85%E4%BB%8B%E7%BB%8D%E5%9B%9B/"><span hidden itemprop="author" itemscope itemtype="http://schema.org/Person"><meta itemprop="image" content="/uploads/avatar.jpg"><meta itemprop="name" content="Nicksxs"></span><span hidden itemprop="publisher" itemscope itemtype="http://schema.org/Organization"><meta itemprop="name" content="Nicksxs's Blog"><meta itemprop="description" content="learn from zero,技术博客，Nicksxs，史学森"></span><span hidden itemprop="post" itemscope itemtype="http://schema.org/CreativeWork"><meta itemprop="name" content="undefined | Nicksxs's Blog"><meta itemprop="description" content=""></span><header class="post-header"><h2 class="post-title" itemprop="name headline"><a href="/2022/12/25/docker%E6%AF%94%E4%B8%80%E8%88%AC%E5%A4%9A%E4%B8%80%E7%82%B9%E7%9A%84%E5%88%9D%E5%AD%A6%E8%80%85%E4%BB%8B%E7%BB%8D%E5%9B%9B/" class="post-title-link" itemprop="url">docker比一般多一点的初学者介绍四</a></h2><div class="post-meta-container"><div class="post-meta"><span class="post-meta-item"><span class="post-meta-item-icon"><i class="far fa-calendar"></i> </span><span class="post-meta-item-text">发表于</span> <time title="创建时间：2022-12-25 19:40:28 / 修改时间：19:41:57" itemprop="dateCreated datePublished" datetime="2022-12-25T19:40:28+08:00">2022-12-25</time> </span><span class="post-meta-item"><span class="post-meta-item-icon"><i class="far fa-folder"></i> </span><span class="post-meta-item-text">分类于</span> <span itemprop="about" itemscope itemtype="http://schema.org/Thing"><a href="/categories/Docker/" itemprop="url" rel="index"><span itemprop="name">Docker</span></a> </span></span><span id="/2022/12/25/docker%E6%AF%94%E4%B8%80%E8%88%AC%E5%A4%9A%E4%B8%80%E7%82%B9%E7%9A%84%E5%88%9D%E5%AD%A6%E8%80%85%E4%BB%8B%E7%BB%8D%E5%9B%9B/" class="post-meta-item leancloud_visitors" data-flag-title="docker比一般多一点的初学者介绍四" title="阅读次数"><span class="post-meta-item-icon"><i class="far fa-eye"></i> </span><span class="post-meta-item-text">阅读次数：</span> <span class="leancloud-visitors-count"></span> </span><span class="post-meta-item"><span class="post-meta-item-icon"><i class="far fa-comment"></i> </span><span class="post-meta-item-text">Disqus：</span> <a title="disqus" href="/2022/12/25/docker%E6%AF%94%E4%B8%80%E8%88%AC%E5%A4%9A%E4%B8%80%E7%82%B9%E7%9A%84%E5%88%9D%E5%AD%A6%E8%80%85%E4%BB%8B%E7%BB%8D%E5%9B%9B/#disqus_thread" itemprop="discussionUrl"><span class="post-comments-count disqus-comment-count" data-disqus-identifier="2022/12/25/docker比一般多一点的初学者介绍四/" itemprop="commentCount"></span></a></span></div></div></header><div class="post-body" itemprop="articleBody"><p>这次单独介绍下docker体系里非常重要的cgroup，docker对资源的限制也是基于cgroup构建的，<br>简单尝试<br>新建一个shell脚本</p><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash"><span class="token shebang important">#!/bin/bash</span>
<span class="token keyword">while</span> <span class="token boolean">true</span><span class="token punctuation">;</span><span class="token keyword">do</span>
<span class="token builtin class-name">echo</span> <span class="token string">"1"</span>
<span class="token keyword">done</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span></span></code></pre><p>直接执行的话就是单核100%的cpu<br><img data-src="https://img.nicksxs.com/blog/rFp7D1.jpg"></p><p>首先在cgroup下面建个目录</p><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash"><span class="token function">mkdir</span> <span class="token parameter variable">-p</span> /sys/fs/cgroup/cpu/sxs_test/<span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><p>查看目录下的文件<br><img data-src="https://img.nicksxs.com/blog/b6UwLR.jpg"><br>其中cpuacct开头的表示cpu相关的统计信息，<br>我们要配置cpu的额度，是在cpu.cfs_quota_us中</p><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash"><span class="token builtin class-name">echo</span> <span class="token number">2000</span> <span class="token operator">></span> /sys/fs/cgroup/cpu/sxs_test/cpu.cfs_quota_us <span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><p>这样表示可以使用2%的cpu，总的配额是在cpu.cfs_period_us中<br><img data-src="https://img.nicksxs.com/blog/oikqB8.png"></p><p>然后将当前进程输入到cgroup.procs,</p><pre class="line-numbers language-bash" data-language="bash"><code class="language-bash"><span class="token builtin class-name">echo</span> <span class="token variable">$$</span> <span class="token operator">></span> /sys/fs/cgroup/cpu/sxs_test/cgroup.procs<span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><p>这样就会自动继承当前进程产生的新进程<br>再次执行就可以看到cpu被限制了<br><img data-src="https://img.nicksxs.com/blog/W0ptVg.png"></p></div><footer class="post-footer"><div class="post-eof"></div></footer></article></div><div class="post-block"><article itemscope itemtype="http://schema.org/Article" class="post-content"><link itemprop="mainEntityOfPage" href="https://nicksxs.me/2022/12/18/mybatis%E7%B3%BB%E5%88%97-%E7%AC%AC%E4%B8%80%E6%9D%A1sql%E7%9A%84%E6%9B%B4%E5%A4%9A%E7%BB%86%E8%8A%82/"><span hidden itemprop="author" itemscope itemtype="http://schema.org/Person"><meta itemprop="image" content="/uploads/avatar.jpg"><meta itemprop="name" content="Nicksxs"></span><span hidden itemprop="publisher" itemscope itemtype="http://schema.org/Organization"><meta itemprop="name" content="Nicksxs's Blog"><meta itemprop="description" content="learn from zero,技术博客，Nicksxs，史学森"></span><span hidden itemprop="post" itemscope itemtype="http://schema.org/CreativeWork"><meta itemprop="name" content="undefined | Nicksxs's Blog"><meta itemprop="description" content=""></span><header class="post-header"><h2 class="post-title" itemprop="name headline"><a href="/2022/12/18/mybatis%E7%B3%BB%E5%88%97-%E7%AC%AC%E4%B8%80%E6%9D%A1sql%E7%9A%84%E6%9B%B4%E5%A4%9A%E7%BB%86%E8%8A%82/" class="post-title-link" itemprop="url">mybatis系列-第一条sql的更多细节</a></h2><div class="post-meta-container"><div class="post-meta"><span class="post-meta-item"><span class="post-meta-item-icon"><i class="far fa-calendar"></i> </span><span class="post-meta-item-text">发表于</span> <time title="创建时间：2022-12-18 21:42:38" itemprop="dateCreated datePublished" datetime="2022-12-18T21:42:38+08:00">2022-12-18</time> </span><span class="post-meta-item"><span class="post-meta-item-icon"><i class="far fa-folder"></i> </span><span class="post-meta-item-text">分类于</span> <span itemprop="about" itemscope itemtype="http://schema.org/Thing"><a href="/categories/Java/" itemprop="url" rel="index"><span itemprop="name">Java</span></a> </span>， <span itemprop="about" itemscope itemtype="http://schema.org/Thing"><a href="/categories/Java/Mybatis/" itemprop="url" rel="index"><span itemprop="name">Mybatis</span></a> </span></span><span id="/2022/12/18/mybatis%E7%B3%BB%E5%88%97-%E7%AC%AC%E4%B8%80%E6%9D%A1sql%E7%9A%84%E6%9B%B4%E5%A4%9A%E7%BB%86%E8%8A%82/" class="post-meta-item leancloud_visitors" data-flag-title="mybatis系列-第一条sql的更多细节" title="阅读次数"><span class="post-meta-item-icon"><i class="far fa-eye"></i> </span><span class="post-meta-item-text">阅读次数：</span> <span class="leancloud-visitors-count"></span> </span><span class="post-meta-item"><span class="post-meta-item-icon"><i class="far fa-comment"></i> </span><span class="post-meta-item-text">Disqus：</span> <a title="disqus" href="/2022/12/18/mybatis%E7%B3%BB%E5%88%97-%E7%AC%AC%E4%B8%80%E6%9D%A1sql%E7%9A%84%E6%9B%B4%E5%A4%9A%E7%BB%86%E8%8A%82/#disqus_thread" itemprop="discussionUrl"><span class="post-comments-count disqus-comment-count" data-disqus-identifier="2022/12/18/mybatis系列-第一条sql的更多细节/" itemprop="commentCount"></span></a></span></div></div></header><div class="post-body" itemprop="articleBody"><p>执行细节<br>首先设置了默认的<code>languageDriver</code><br><code>org/mybatis/mybatis/3.5.11/mybatis-3.5.11-sources.jar!/org/apache/ibatis/session/Configuration.java:215</code><br>在<code>configuration</code>的构造方法里</p><pre class="line-numbers language-java" data-language="java"><code class="language-java">languageRegistry<span class="token punctuation">.</span><span class="token function">setDefaultDriverClass</span><span class="token punctuation">(</span><span class="token class-name">XMLLanguageDriver</span><span class="token punctuation">.</span><span class="token keyword">class</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><p>而在<br><code>org.apache.ibatis.builder.xml.XMLStatementBuilder#parseStatementNode</code><br>中，创建了<code>sqlSource</code>，这里就会根据前面的 <code>LanguageDriver</code> 的实现选择对应的 <code>sqlSource</code> ，</p><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token class-name">SqlSource</span> sqlSource <span class="token operator">=</span> langDriver<span class="token punctuation">.</span><span class="token function">createSqlSource</span><span class="token punctuation">(</span>configuration<span class="token punctuation">,</span> context<span class="token punctuation">,</span> parameterTypeClass<span class="token punctuation">)</span><span class="token punctuation">;</span><span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><p><code>createSqlSource</code> 就会调用</p><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token annotation punctuation">@Override</span>
<span class="token keyword">public</span> <span class="token class-name">SqlSource</span> <span class="token function">createSqlSource</span><span class="token punctuation">(</span><span class="token class-name">Configuration</span> configuration<span class="token punctuation">,</span> <span class="token class-name">XNode</span> script<span class="token punctuation">,</span> <span class="token class-name">Class</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token operator">?</span><span class="token punctuation">></span></span> parameterType<span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token class-name">XMLScriptBuilder</span> builder <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">XMLScriptBuilder</span><span class="token punctuation">(</span>configuration<span class="token punctuation">,</span> script<span class="token punctuation">,</span> parameterType<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">return</span> builder<span class="token punctuation">.</span><span class="token function">parseScriptNode</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>再往下的逻辑在 <code>parseScriptNode</code> 中，<code>org.apache.ibatis.scripting.xmltags.XMLScriptBuilder#parseScriptNode</code></p><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token keyword">public</span> <span class="token class-name">SqlSource</span> <span class="token function">parseScriptNode</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token class-name">MixedSqlNode</span> rootSqlNode <span class="token operator">=</span> <span class="token function">parseDynamicTags</span><span class="token punctuation">(</span>context<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token class-name">SqlSource</span> sqlSource<span class="token punctuation">;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>isDynamic<span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
sqlSource <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">DynamicSqlSource</span><span class="token punctuation">(</span>configuration<span class="token punctuation">,</span> rootSqlNode<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span> <span class="token keyword">else</span> <span class="token punctuation">&#123;</span>
sqlSource <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">RawSqlSource</span><span class="token punctuation">(</span>configuration<span class="token punctuation">,</span> rootSqlNode<span class="token punctuation">,</span> parameterType<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token keyword">return</span> sqlSource<span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>首先要解析<code>dynamicTag</code>，调用了<code>org.apache.ibatis.scripting.xmltags.XMLScriptBuilder#parseDynamicTags</code></p><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token keyword">protected</span> <span class="token class-name">MixedSqlNode</span> <span class="token function">parseDynamicTags</span><span class="token punctuation">(</span><span class="token class-name">XNode</span> node<span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token class-name">List</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">SqlNode</span><span class="token punctuation">></span></span> contents <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">ArrayList</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token punctuation">></span></span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token class-name">NodeList</span> children <span class="token operator">=</span> node<span class="token punctuation">.</span><span class="token function">getNode</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">getChildNodes</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">for</span> <span class="token punctuation">(</span><span class="token keyword">int</span> i <span class="token operator">=</span> <span class="token number">0</span><span class="token punctuation">;</span> i <span class="token operator">&lt;</span> children<span class="token punctuation">.</span><span class="token function">getLength</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> i<span class="token operator">++</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token class-name">XNode</span> child <span class="token operator">=</span> node<span class="token punctuation">.</span><span class="token function">newXNode</span><span class="token punctuation">(</span>children<span class="token punctuation">.</span><span class="token function">item</span><span class="token punctuation">(</span>i<span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>child<span class="token punctuation">.</span><span class="token function">getNode</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">getNodeType</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator">==</span> <span class="token class-name">Node</span><span class="token punctuation">.</span><span class="token constant">CDATA_SECTION_NODE</span> <span class="token operator">||</span> child<span class="token punctuation">.</span><span class="token function">getNode</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">getNodeType</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator">==</span> <span class="token class-name">Node</span><span class="token punctuation">.</span><span class="token constant">TEXT_NODE</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token class-name">String</span> data <span class="token operator">=</span> child<span class="token punctuation">.</span><span class="token function">getStringBody</span><span class="token punctuation">(</span><span class="token string">""</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token class-name">TextSqlNode</span> textSqlNode <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">TextSqlNode</span><span class="token punctuation">(</span>data<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token comment">// ---------> 主要是这边的逻辑</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>textSqlNode<span class="token punctuation">.</span><span class="token function">isDynamic</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
contents<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span>textSqlNode<span class="token punctuation">)</span><span class="token punctuation">;</span>
isDynamic <span class="token operator">=</span> <span class="token boolean">true</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span> <span class="token keyword">else</span> <span class="token punctuation">&#123;</span>
contents<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span><span class="token keyword">new</span> <span class="token class-name">StaticTextSqlNode</span><span class="token punctuation">(</span>data<span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token punctuation">&#125;</span> <span class="token keyword">else</span> <span class="token keyword">if</span> <span class="token punctuation">(</span>child<span class="token punctuation">.</span><span class="token function">getNode</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">getNodeType</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator">==</span> <span class="token class-name">Node</span><span class="token punctuation">.</span><span class="token constant">ELEMENT_NODE</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span> <span class="token comment">// issue #628</span>
<span class="token class-name">String</span> nodeName <span class="token operator">=</span> child<span class="token punctuation">.</span><span class="token function">getNode</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">getNodeName</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token class-name">NodeHandler</span> handler <span class="token operator">=</span> nodeHandlerMap<span class="token punctuation">.</span><span class="token function">get</span><span class="token punctuation">(</span>nodeName<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>handler <span class="token operator">==</span> <span class="token keyword">null</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">throw</span> <span class="token keyword">new</span> <span class="token class-name">BuilderException</span><span class="token punctuation">(</span><span class="token string">"Unknown element &lt;"</span> <span class="token operator">+</span> nodeName <span class="token operator">+</span> <span class="token string">"> in SQL statement."</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
handler<span class="token punctuation">.</span><span class="token function">handleNode</span><span class="token punctuation">(</span>child<span class="token punctuation">,</span> contents<span class="token punctuation">)</span><span class="token punctuation">;</span>
isDynamic <span class="token operator">=</span> <span class="token boolean">true</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token punctuation">&#125;</span>
<span class="token keyword">return</span> <span class="token keyword">new</span> <span class="token class-name">MixedSqlNode</span><span class="token punctuation">(</span>contents<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>判断是否是动态<code>sql</code>，调用了<code>org.apache.ibatis.scripting.xmltags.TextSqlNode#isDynamic</code></p><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token keyword">public</span> <span class="token keyword">boolean</span> <span class="token function">isDynamic</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token class-name">DynamicCheckerTokenParser</span> checker <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">DynamicCheckerTokenParser</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token comment">// ----------> 主要是这里的方法</span>
<span class="token class-name">GenericTokenParser</span> parser <span class="token operator">=</span> <span class="token function">createParser</span><span class="token punctuation">(</span>checker<span class="token punctuation">)</span><span class="token punctuation">;</span>
parser<span class="token punctuation">.</span><span class="token function">parse</span><span class="token punctuation">(</span>text<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">return</span> checker<span class="token punctuation">.</span><span class="token function">isDynamic</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>创建<code>parser</code>的时候可以看到这个<code>parser</code>是干了啥，其实就是找有没有<code>$&#123;</code> , <code>&#125;</code></p><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token keyword">private</span> <span class="token class-name">GenericTokenParser</span> <span class="token function">createParser</span><span class="token punctuation">(</span><span class="token class-name">TokenHandler</span> handler<span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">return</span> <span class="token keyword">new</span> <span class="token class-name">GenericTokenParser</span><span class="token punctuation">(</span><span class="token string">"$&#123;"</span><span class="token punctuation">,</span> <span class="token string">"&#125;"</span><span class="token punctuation">,</span> handler<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span></span></code></pre><p>如果是的话，就在上面把 <code>isDynamic</code> 设置为<code>true</code> 如果是<code>true</code> 的话就创建 <code>DynamicSqlSource</code></p><pre class="line-numbers language-java" data-language="java"><code class="language-java">sqlSource <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">DynamicSqlSource</span><span class="token punctuation">(</span>configuration<span class="token punctuation">,</span> rootSqlNode<span class="token punctuation">)</span><span class="token punctuation">;</span><span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><p>如果不是的话就创建<code>RawSqlSource</code></p><pre class="line-numbers language-java" data-language="java"><code class="language-java">sqlSource <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">RawSqlSource</span><span class="token punctuation">(</span>configuration<span class="token punctuation">,</span> rootSqlNode<span class="token punctuation">,</span> parameterType<span class="token punctuation">)</span><span class="token punctuation">;</span>
```java
但是这不是一个真实可用的 `sqlSource` ，
实际创建的时候会走到这
```java
<span class="token keyword">public</span> <span class="token class-name">RawSqlSource</span><span class="token punctuation">(</span><span class="token class-name">Configuration</span> configuration<span class="token punctuation">,</span> <span class="token class-name">SqlNode</span> rootSqlNode<span class="token punctuation">,</span> <span class="token class-name">Class</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token operator">?</span><span class="token punctuation">></span></span> parameterType<span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">this</span><span class="token punctuation">(</span>configuration<span class="token punctuation">,</span> <span class="token function">getSql</span><span class="token punctuation">(</span>configuration<span class="token punctuation">,</span> rootSqlNode<span class="token punctuation">)</span><span class="token punctuation">,</span> parameterType<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token keyword">public</span> <span class="token class-name">RawSqlSource</span><span class="token punctuation">(</span><span class="token class-name">Configuration</span> configuration<span class="token punctuation">,</span> <span class="token class-name">String</span> sql<span class="token punctuation">,</span> <span class="token class-name">Class</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token operator">?</span><span class="token punctuation">></span></span> parameterType<span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token class-name">SqlSourceBuilder</span> sqlSourceParser <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">SqlSourceBuilder</span><span class="token punctuation">(</span>configuration<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token class-name">Class</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token operator">?</span><span class="token punctuation">></span></span> clazz <span class="token operator">=</span> parameterType <span class="token operator">==</span> <span class="token keyword">null</span> <span class="token operator">?</span> <span class="token class-name">Object</span><span class="token punctuation">.</span><span class="token keyword">class</span> <span class="token operator">:</span> parameterType<span class="token punctuation">;</span>
sqlSource <span class="token operator">=</span> sqlSourceParser<span class="token punctuation">.</span><span class="token function">parse</span><span class="token punctuation">(</span>sql<span class="token punctuation">,</span> clazz<span class="token punctuation">,</span> <span class="token keyword">new</span> <span class="token class-name">HashMap</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token punctuation">></span></span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>具体的<code>sqlSource</code>是通过<code>org.apache.ibatis.builder.SqlSourceBuilder#parse</code> 创建的<br>具体的代码逻辑是</p><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token keyword">public</span> <span class="token class-name">SqlSource</span> <span class="token function">parse</span><span class="token punctuation">(</span><span class="token class-name">String</span> originalSql<span class="token punctuation">,</span> <span class="token class-name">Class</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token operator">?</span><span class="token punctuation">></span></span> parameterType<span class="token punctuation">,</span> <span class="token class-name">Map</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">String</span><span class="token punctuation">,</span> <span class="token class-name">Object</span><span class="token punctuation">></span></span> additionalParameters<span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token class-name">ParameterMappingTokenHandler</span> handler <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">ParameterMappingTokenHandler</span><span class="token punctuation">(</span>configuration<span class="token punctuation">,</span> parameterType<span class="token punctuation">,</span> additionalParameters<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token class-name">GenericTokenParser</span> parser <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">GenericTokenParser</span><span class="token punctuation">(</span><span class="token string">"#&#123;"</span><span class="token punctuation">,</span> <span class="token string">"&#125;"</span><span class="token punctuation">,</span> handler<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token class-name">String</span> sql<span class="token punctuation">;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>configuration<span class="token punctuation">.</span><span class="token function">isShrinkWhitespacesInSql</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
sql <span class="token operator">=</span> parser<span class="token punctuation">.</span><span class="token function">parse</span><span class="token punctuation">(</span><span class="token function">removeExtraWhitespaces</span><span class="token punctuation">(</span>originalSql<span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span> <span class="token keyword">else</span> <span class="token punctuation">&#123;</span>
sql <span class="token operator">=</span> parser<span class="token punctuation">.</span><span class="token function">parse</span><span class="token punctuation">(</span>originalSql<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token keyword">return</span> <span class="token keyword">new</span> <span class="token class-name">StaticSqlSource</span><span class="token punctuation">(</span>configuration<span class="token punctuation">,</span> sql<span class="token punctuation">,</span> handler<span class="token punctuation">.</span><span class="token function">getParameterMappings</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>这里创建的其实是<code>StaticSqlSource</code> ,多带一句前面的<code>parser</code>是将原来这样<code>select * from student where id = #&#123;id&#125;</code> 的 <code>sql</code> 解析成了<code>select * from student where id = ?</code> 然后创建了<code>StaticSqlSource</code></p><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token keyword">public</span> <span class="token class-name">StaticSqlSource</span><span class="token punctuation">(</span><span class="token class-name">Configuration</span> configuration<span class="token punctuation">,</span> <span class="token class-name">String</span> sql<span class="token punctuation">,</span> <span class="token class-name">List</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">ParameterMapping</span><span class="token punctuation">></span></span> parameterMappings<span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">this</span><span class="token punctuation">.</span>sql <span class="token operator">=</span> sql<span class="token punctuation">;</span>
<span class="token keyword">this</span><span class="token punctuation">.</span>parameterMappings <span class="token operator">=</span> parameterMappings<span class="token punctuation">;</span>
<span class="token keyword">this</span><span class="token punctuation">.</span>configuration <span class="token operator">=</span> configuration<span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>为什么前面要讲这么多好像没什么关系的代码呢，其实在最开始我们执行<code>sql</code>的代码中</p><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token annotation punctuation">@Override</span>
<span class="token keyword">public</span> <span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">E</span><span class="token punctuation">></span></span> <span class="token class-name">List</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">E</span><span class="token punctuation">></span></span> <span class="token function">query</span><span class="token punctuation">(</span><span class="token class-name">MappedStatement</span> ms<span class="token punctuation">,</span> <span class="token class-name">Object</span> parameterObject<span class="token punctuation">,</span> <span class="token class-name">RowBounds</span> rowBounds<span class="token punctuation">,</span> <span class="token class-name">ResultHandler</span> resultHandler<span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">SQLException</span> <span class="token punctuation">&#123;</span>
<span class="token class-name">BoundSql</span> boundSql <span class="token operator">=</span> ms<span class="token punctuation">.</span><span class="token function">getBoundSql</span><span class="token punctuation">(</span>parameterObject<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token class-name">CacheKey</span> key <span class="token operator">=</span> <span class="token function">createCacheKey</span><span class="token punctuation">(</span>ms<span class="token punctuation">,</span> parameterObject<span class="token punctuation">,</span> rowBounds<span class="token punctuation">,</span> boundSql<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">return</span> <span class="token function">query</span><span class="token punctuation">(</span>ms<span class="token punctuation">,</span> parameterObject<span class="token punctuation">,</span> rowBounds<span class="token punctuation">,</span> resultHandler<span class="token punctuation">,</span> key<span class="token punctuation">,</span> boundSql<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>这里获取了<code>BoundSql</code>，而<code>BoundSql</code>是怎么来的呢，首先调用了<code>org.apache.ibatis.mapping.MappedStatement#getBoundSql</code></p><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token keyword">public</span> <span class="token class-name">BoundSql</span> <span class="token function">getBoundSql</span><span class="token punctuation">(</span><span class="token class-name">Object</span> parameterObject<span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token class-name">BoundSql</span> boundSql <span class="token operator">=</span> sqlSource<span class="token punctuation">.</span><span class="token function">getBoundSql</span><span class="token punctuation">(</span>parameterObject<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token class-name">List</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">ParameterMapping</span><span class="token punctuation">></span></span> parameterMappings <span class="token operator">=</span> boundSql<span class="token punctuation">.</span><span class="token function">getParameterMappings</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>parameterMappings <span class="token operator">==</span> <span class="token keyword">null</span> <span class="token operator">||</span> parameterMappings<span class="token punctuation">.</span><span class="token function">isEmpty</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
boundSql <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">BoundSql</span><span class="token punctuation">(</span>configuration<span class="token punctuation">,</span> boundSql<span class="token punctuation">.</span><span class="token function">getSql</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">,</span> parameterMap<span class="token punctuation">.</span><span class="token function">getParameterMappings</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">,</span> parameterObject<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token comment">// check for nested result maps in parameter mappings (issue #30)</span>
<span class="token keyword">for</span> <span class="token punctuation">(</span><span class="token class-name">ParameterMapping</span> pm <span class="token operator">:</span> boundSql<span class="token punctuation">.</span><span class="token function">getParameterMappings</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token class-name">String</span> rmId <span class="token operator">=</span> pm<span class="token punctuation">.</span><span class="token function">getResultMapId</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>rmId <span class="token operator">!=</span> <span class="token keyword">null</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token class-name">ResultMap</span> rm <span class="token operator">=</span> configuration<span class="token punctuation">.</span><span class="token function">getResultMap</span><span class="token punctuation">(</span>rmId<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>rm <span class="token operator">!=</span> <span class="token keyword">null</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
hasNestedResultMaps <span class="token operator">|=</span> rm<span class="token punctuation">.</span><span class="token function">hasNestedResultMaps</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token punctuation">&#125;</span>
<span class="token punctuation">&#125;</span>
<span class="token keyword">return</span> boundSql<span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>而我们从上面的解析中可以看到这里的<code>sqlSource</code>是一层<code>RawSqlSource</code> , 它的<code>getBoundSql</code>又是调用内部的<code>sqlSource</code>的方法</p><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token annotation punctuation">@Override</span>
<span class="token keyword">public</span> <span class="token class-name">BoundSql</span> <span class="token function">getBoundSql</span><span class="token punctuation">(</span><span class="token class-name">Object</span> parameterObject<span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">return</span> sqlSource<span class="token punctuation">.</span><span class="token function">getBoundSql</span><span class="token punctuation">(</span>parameterObject<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span></span></code></pre><p>内部的<code>sqlSource</code> 就是<code>StaticSqlSource</code> ，</p><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token annotation punctuation">@Override</span>
<span class="token keyword">public</span> <span class="token class-name">BoundSql</span> <span class="token function">getBoundSql</span><span class="token punctuation">(</span><span class="token class-name">Object</span> parameterObject<span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">return</span> <span class="token keyword">new</span> <span class="token class-name">BoundSql</span><span class="token punctuation">(</span>configuration<span class="token punctuation">,</span> sql<span class="token punctuation">,</span> parameterMappings<span class="token punctuation">,</span> parameterObject<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span></span></code></pre><p>这个<code>BoundSql</code>的内容也比较简单</p><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token keyword">public</span> <span class="token class-name">BoundSql</span><span class="token punctuation">(</span><span class="token class-name">Configuration</span> configuration<span class="token punctuation">,</span> <span class="token class-name">String</span> sql<span class="token punctuation">,</span> <span class="token class-name">List</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">ParameterMapping</span><span class="token punctuation">></span></span> parameterMappings<span class="token punctuation">,</span> <span class="token class-name">Object</span> parameterObject<span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">this</span><span class="token punctuation">.</span>sql <span class="token operator">=</span> sql<span class="token punctuation">;</span>
<span class="token keyword">this</span><span class="token punctuation">.</span>parameterMappings <span class="token operator">=</span> parameterMappings<span class="token punctuation">;</span>
<span class="token keyword">this</span><span class="token punctuation">.</span>parameterObject <span class="token operator">=</span> parameterObject<span class="token punctuation">;</span>
<span class="token keyword">this</span><span class="token punctuation">.</span>additionalParameters <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">HashMap</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token punctuation">></span></span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">this</span><span class="token punctuation">.</span>metaParameters <span class="token operator">=</span> configuration<span class="token punctuation">.</span><span class="token function">newMetaObject</span><span class="token punctuation">(</span>additionalParameters<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>而上次在这边<code>org.apache.ibatis.executor.SimpleExecutor#doQuery</code> 的时候落了个东西，就是<code>StatementHandler</code>的逻辑</p><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token annotation punctuation">@Override</span>
<span class="token keyword">public</span> <span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">E</span><span class="token punctuation">></span></span> <span class="token class-name">List</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">E</span><span class="token punctuation">></span></span> <span class="token function">doQuery</span><span class="token punctuation">(</span><span class="token class-name">MappedStatement</span> ms<span class="token punctuation">,</span> <span class="token class-name">Object</span> parameter<span class="token punctuation">,</span> <span class="token class-name">RowBounds</span> rowBounds<span class="token punctuation">,</span> <span class="token class-name">ResultHandler</span> resultHandler<span class="token punctuation">,</span> <span class="token class-name">BoundSql</span> boundSql<span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">SQLException</span> <span class="token punctuation">&#123;</span>
<span class="token class-name">Statement</span> stmt <span class="token operator">=</span> <span class="token keyword">null</span><span class="token punctuation">;</span>
<span class="token keyword">try</span> <span class="token punctuation">&#123;</span>
<span class="token class-name">Configuration</span> configuration <span class="token operator">=</span> ms<span class="token punctuation">.</span><span class="token function">getConfiguration</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token class-name">StatementHandler</span> handler <span class="token operator">=</span> configuration<span class="token punctuation">.</span><span class="token function">newStatementHandler</span><span class="token punctuation">(</span>wrapper<span class="token punctuation">,</span> ms<span class="token punctuation">,</span> parameter<span class="token punctuation">,</span> rowBounds<span class="token punctuation">,</span> resultHandler<span class="token punctuation">,</span> boundSql<span class="token punctuation">)</span><span class="token punctuation">;</span>
stmt <span class="token operator">=</span> <span class="token function">prepareStatement</span><span class="token punctuation">(</span>handler<span class="token punctuation">,</span> ms<span class="token punctuation">.</span><span class="token function">getStatementLog</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">return</span> handler<span class="token punctuation">.</span><span class="token function">query</span><span class="token punctuation">(</span>stmt<span class="token punctuation">,</span> resultHandler<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span> <span class="token keyword">finally</span> <span class="token punctuation">&#123;</span>
<span class="token function">closeStatement</span><span class="token punctuation">(</span>stmt<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token punctuation">&#125;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>它是通过statementType来区分应该使用哪个statementHandler，我们这使用的就是PreparedStatementHandler</p><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token keyword">public</span> <span class="token class-name">RoutingStatementHandler</span><span class="token punctuation">(</span><span class="token class-name">Executor</span> executor<span class="token punctuation">,</span> <span class="token class-name">MappedStatement</span> ms<span class="token punctuation">,</span> <span class="token class-name">Object</span> parameter<span class="token punctuation">,</span> <span class="token class-name">RowBounds</span> rowBounds<span class="token punctuation">,</span> <span class="token class-name">ResultHandler</span> resultHandler<span class="token punctuation">,</span> <span class="token class-name">BoundSql</span> boundSql<span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">switch</span> <span class="token punctuation">(</span>ms<span class="token punctuation">.</span><span class="token function">getStatementType</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">case</span> <span class="token constant">STATEMENT</span><span class="token operator">:</span>
delegate <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">SimpleStatementHandler</span><span class="token punctuation">(</span>executor<span class="token punctuation">,</span> ms<span class="token punctuation">,</span> parameter<span class="token punctuation">,</span> rowBounds<span class="token punctuation">,</span> resultHandler<span class="token punctuation">,</span> boundSql<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">break</span><span class="token punctuation">;</span>
<span class="token keyword">case</span> <span class="token constant">PREPARED</span><span class="token operator">:</span>
delegate <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">PreparedStatementHandler</span><span class="token punctuation">(</span>executor<span class="token punctuation">,</span> ms<span class="token punctuation">,</span> parameter<span class="token punctuation">,</span> rowBounds<span class="token punctuation">,</span> resultHandler<span class="token punctuation">,</span> boundSql<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">break</span><span class="token punctuation">;</span>
<span class="token keyword">case</span> <span class="token constant">CALLABLE</span><span class="token operator">:</span>
delegate <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">CallableStatementHandler</span><span class="token punctuation">(</span>executor<span class="token punctuation">,</span> ms<span class="token punctuation">,</span> parameter<span class="token punctuation">,</span> rowBounds<span class="token punctuation">,</span> resultHandler<span class="token punctuation">,</span> boundSql<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">break</span><span class="token punctuation">;</span>
<span class="token keyword">default</span><span class="token operator">:</span>
<span class="token keyword">throw</span> <span class="token keyword">new</span> <span class="token class-name">ExecutorException</span><span class="token punctuation">(</span><span class="token string">"Unknown statement type: "</span> <span class="token operator">+</span> ms<span class="token punctuation">.</span><span class="token function">getStatementType</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token punctuation">&#125;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>所以上次有个细节可以补充，这边的doQuery里面的handler.query 应该是调用了PreparedStatementHandler 的query方法</p><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token annotation punctuation">@Override</span>
<span class="token keyword">public</span> <span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">E</span><span class="token punctuation">></span></span> <span class="token class-name">List</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">E</span><span class="token punctuation">></span></span> <span class="token function">doQuery</span><span class="token punctuation">(</span><span class="token class-name">MappedStatement</span> ms<span class="token punctuation">,</span> <span class="token class-name">Object</span> parameter<span class="token punctuation">,</span> <span class="token class-name">RowBounds</span> rowBounds<span class="token punctuation">,</span> <span class="token class-name">ResultHandler</span> resultHandler<span class="token punctuation">,</span> <span class="token class-name">BoundSql</span> boundSql<span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">SQLException</span> <span class="token punctuation">&#123;</span>
<span class="token class-name">Statement</span> stmt <span class="token operator">=</span> <span class="token keyword">null</span><span class="token punctuation">;</span>
<span class="token keyword">try</span> <span class="token punctuation">&#123;</span>
<span class="token class-name">Configuration</span> configuration <span class="token operator">=</span> ms<span class="token punctuation">.</span><span class="token function">getConfiguration</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token class-name">StatementHandler</span> handler <span class="token operator">=</span> configuration<span class="token punctuation">.</span><span class="token function">newStatementHandler</span><span class="token punctuation">(</span>wrapper<span class="token punctuation">,</span> ms<span class="token punctuation">,</span> parameter<span class="token punctuation">,</span> rowBounds<span class="token punctuation">,</span> resultHandler<span class="token punctuation">,</span> boundSql<span class="token punctuation">)</span><span class="token punctuation">;</span>
stmt <span class="token operator">=</span> <span class="token function">prepareStatement</span><span class="token punctuation">(</span>handler<span class="token punctuation">,</span> ms<span class="token punctuation">.</span><span class="token function">getStatementLog</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">return</span> handler<span class="token punctuation">.</span><span class="token function">query</span><span class="token punctuation">(</span>stmt<span class="token punctuation">,</span> resultHandler<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span> <span class="token keyword">finally</span> <span class="token punctuation">&#123;</span>
<span class="token function">closeStatement</span><span class="token punctuation">(</span>stmt<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token punctuation">&#125;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>因为上面prepareStatement中getConnection拿到connection是com.mysql.cj.jdbc.ConnectionImpl#ConnectionImpl(com.mysql.cj.conf.HostInfo)</p><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token annotation punctuation">@Override</span>
<span class="token keyword">public</span> <span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">E</span><span class="token punctuation">></span></span> <span class="token class-name">List</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">E</span><span class="token punctuation">></span></span> <span class="token function">query</span><span class="token punctuation">(</span><span class="token class-name">Statement</span> statement<span class="token punctuation">,</span> <span class="token class-name">ResultHandler</span> resultHandler<span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">SQLException</span> <span class="token punctuation">&#123;</span>
<span class="token class-name">PreparedStatement</span> ps <span class="token operator">=</span> <span class="token punctuation">(</span><span class="token class-name">PreparedStatement</span><span class="token punctuation">)</span> statement<span class="token punctuation">;</span>
ps<span class="token punctuation">.</span><span class="token function">execute</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">return</span> resultSetHandler<span class="token punctuation">.</span><span class="token function">handleResultSets</span><span class="token punctuation">(</span>ps<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>那又为什么是这个呢，可以在网上找，我们在mybatis-config.xml里配置的</p><pre class="line-numbers language-markup" data-language="markup"><code class="language-markup"><span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>transactionManager</span> <span class="token attr-name">type</span><span class="token attr-value"><span class="token punctuation attr-equals">=</span><span class="token punctuation">"</span>JDBC<span class="token punctuation">"</span></span><span class="token punctuation">/></span></span><span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre><p>因此在parseConfiguration中配置environment时</p><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token keyword">private</span> <span class="token keyword">void</span> <span class="token function">parseConfiguration</span><span class="token punctuation">(</span><span class="token class-name">XNode</span> root<span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">try</span> <span class="token punctuation">&#123;</span>
<span class="token comment">// issue #117 read properties first</span>
<span class="token function">propertiesElement</span><span class="token punctuation">(</span>root<span class="token punctuation">.</span><span class="token function">evalNode</span><span class="token punctuation">(</span><span class="token string">"properties"</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token class-name">Properties</span> settings <span class="token operator">=</span> <span class="token function">settingsAsProperties</span><span class="token punctuation">(</span>root<span class="token punctuation">.</span><span class="token function">evalNode</span><span class="token punctuation">(</span><span class="token string">"settings"</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token function">loadCustomVfs</span><span class="token punctuation">(</span>settings<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token function">loadCustomLogImpl</span><span class="token punctuation">(</span>settings<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token function">typeAliasesElement</span><span class="token punctuation">(</span>root<span class="token punctuation">.</span><span class="token function">evalNode</span><span class="token punctuation">(</span><span class="token string">"typeAliases"</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token function">pluginElement</span><span class="token punctuation">(</span>root<span class="token punctuation">.</span><span class="token function">evalNode</span><span class="token punctuation">(</span><span class="token string">"plugins"</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token function">objectFactoryElement</span><span class="token punctuation">(</span>root<span class="token punctuation">.</span><span class="token function">evalNode</span><span class="token punctuation">(</span><span class="token string">"objectFactory"</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token function">objectWrapperFactoryElement</span><span class="token punctuation">(</span>root<span class="token punctuation">.</span><span class="token function">evalNode</span><span class="token punctuation">(</span><span class="token string">"objectWrapperFactory"</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token function">reflectorFactoryElement</span><span class="token punctuation">(</span>root<span class="token punctuation">.</span><span class="token function">evalNode</span><span class="token punctuation">(</span><span class="token string">"reflectorFactory"</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token function">settingsElement</span><span class="token punctuation">(</span>settings<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token comment">// read it after objectFactory and objectWrapperFactory issue #631</span>
<span class="token comment">// ----------> 就是这里</span>
<span class="token function">environmentsElement</span><span class="token punctuation">(</span>root<span class="token punctuation">.</span><span class="token function">evalNode</span><span class="token punctuation">(</span><span class="token string">"environments"</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token function">databaseIdProviderElement</span><span class="token punctuation">(</span>root<span class="token punctuation">.</span><span class="token function">evalNode</span><span class="token punctuation">(</span><span class="token string">"databaseIdProvider"</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token function">typeHandlerElement</span><span class="token punctuation">(</span>root<span class="token punctuation">.</span><span class="token function">evalNode</span><span class="token punctuation">(</span><span class="token string">"typeHandlers"</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token function">mapperElement</span><span class="token punctuation">(</span>root<span class="token punctuation">.</span><span class="token function">evalNode</span><span class="token punctuation">(</span><span class="token string">"mappers"</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span> <span class="token keyword">catch</span> <span class="token punctuation">(</span><span class="token class-name">Exception</span> e<span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">throw</span> <span class="token keyword">new</span> <span class="token class-name">BuilderException</span><span class="token punctuation">(</span><span class="token string">"Error parsing SQL Mapper Configuration. Cause: "</span> <span class="token operator">+</span> e<span class="token punctuation">,</span> e<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token punctuation">&#125;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>调用的这个方法通过获取xml中的transactionManager 配置的类型，也就是JDBC</p><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token keyword">private</span> <span class="token keyword">void</span> <span class="token function">environmentsElement</span><span class="token punctuation">(</span><span class="token class-name">XNode</span> context<span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">Exception</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>context <span class="token operator">!=</span> <span class="token keyword">null</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>environment <span class="token operator">==</span> <span class="token keyword">null</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
environment <span class="token operator">=</span> context<span class="token punctuation">.</span><span class="token function">getStringAttribute</span><span class="token punctuation">(</span><span class="token string">"default"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token keyword">for</span> <span class="token punctuation">(</span><span class="token class-name">XNode</span> child <span class="token operator">:</span> context<span class="token punctuation">.</span><span class="token function">getChildren</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token class-name">String</span> id <span class="token operator">=</span> child<span class="token punctuation">.</span><span class="token function">getStringAttribute</span><span class="token punctuation">(</span><span class="token string">"id"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span><span class="token function">isSpecifiedEnvironment</span><span class="token punctuation">(</span>id<span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token comment">// -------> 找到这里</span>
<span class="token class-name">TransactionFactory</span> txFactory <span class="token operator">=</span> <span class="token function">transactionManagerElement</span><span class="token punctuation">(</span>child<span class="token punctuation">.</span><span class="token function">evalNode</span><span class="token punctuation">(</span><span class="token string">"transactionManager"</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token class-name">DataSourceFactory</span> dsFactory <span class="token operator">=</span> <span class="token function">dataSourceElement</span><span class="token punctuation">(</span>child<span class="token punctuation">.</span><span class="token function">evalNode</span><span class="token punctuation">(</span><span class="token string">"dataSource"</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token class-name">DataSource</span> dataSource <span class="token operator">=</span> dsFactory<span class="token punctuation">.</span><span class="token function">getDataSource</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token class-name">Environment<span class="token punctuation">.</span>Builder</span> environmentBuilder <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">Environment<span class="token punctuation">.</span>Builder</span><span class="token punctuation">(</span>id<span class="token punctuation">)</span>
<span class="token punctuation">.</span><span class="token function">transactionFactory</span><span class="token punctuation">(</span>txFactory<span class="token punctuation">)</span>
<span class="token punctuation">.</span><span class="token function">dataSource</span><span class="token punctuation">(</span>dataSource<span class="token punctuation">)</span><span class="token punctuation">;</span>
configuration<span class="token punctuation">.</span><span class="token function">setEnvironment</span><span class="token punctuation">(</span>environmentBuilder<span class="token punctuation">.</span><span class="token function">build</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">break</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token punctuation">&#125;</span>
<span class="token punctuation">&#125;</span>
<span class="token punctuation">&#125;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>是通过以下方法获取的，</p><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token comment">// 方法全限定名 org.apache.ibatis.builder.xml.XMLConfigBuilder#transactionManagerElement</span>
<span class="token keyword">private</span> <span class="token class-name">TransactionFactory</span> <span class="token function">transactionManagerElement</span><span class="token punctuation">(</span><span class="token class-name">XNode</span> context<span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">Exception</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>context <span class="token operator">!=</span> <span class="token keyword">null</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token class-name">String</span> type <span class="token operator">=</span> context<span class="token punctuation">.</span><span class="token function">getStringAttribute</span><span class="token punctuation">(</span><span class="token string">"type"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token class-name">Properties</span> props <span class="token operator">=</span> context<span class="token punctuation">.</span><span class="token function">getChildrenAsProperties</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token class-name">TransactionFactory</span> factory <span class="token operator">=</span> <span class="token punctuation">(</span><span class="token class-name">TransactionFactory</span><span class="token punctuation">)</span> <span class="token function">resolveClass</span><span class="token punctuation">(</span>type<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">getDeclaredConstructor</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">newInstance</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
factory<span class="token punctuation">.</span><span class="token function">setProperties</span><span class="token punctuation">(</span>props<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">return</span> factory<span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token keyword">throw</span> <span class="token keyword">new</span> <span class="token class-name">BuilderException</span><span class="token punctuation">(</span><span class="token string">"Environment declaration requires a TransactionFactory."</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token comment">// 方法全限定名 org.apache.ibatis.builder.BaseBuilder#resolveClass</span>
<span class="token keyword">protected</span> <span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">T</span><span class="token punctuation">></span></span> <span class="token class-name">Class</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token operator">?</span> <span class="token keyword">extends</span> <span class="token class-name">T</span><span class="token punctuation">></span></span> <span class="token function">resolveClass</span><span class="token punctuation">(</span><span class="token class-name">String</span> alias<span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>alias <span class="token operator">==</span> <span class="token keyword">null</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">return</span> <span class="token keyword">null</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token keyword">try</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">return</span> <span class="token function">resolveAlias</span><span class="token punctuation">(</span>alias<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span> <span class="token keyword">catch</span> <span class="token punctuation">(</span><span class="token class-name">Exception</span> e<span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">throw</span> <span class="token keyword">new</span> <span class="token class-name">BuilderException</span><span class="token punctuation">(</span><span class="token string">"Error resolving class. Cause: "</span> <span class="token operator">+</span> e<span class="token punctuation">,</span> e<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token punctuation">&#125;</span>
<span class="token comment">// 方法全限定名 org.apache.ibatis.builder.BaseBuilder#resolveAlias</span>
<span class="token keyword">protected</span> <span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">T</span><span class="token punctuation">></span></span> <span class="token class-name">Class</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token operator">?</span> <span class="token keyword">extends</span> <span class="token class-name">T</span><span class="token punctuation">></span></span> <span class="token function">resolveAlias</span><span class="token punctuation">(</span><span class="token class-name">String</span> alias<span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">return</span> typeAliasRegistry<span class="token punctuation">.</span><span class="token function">resolveAlias</span><span class="token punctuation">(</span>alias<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token comment">// 方法全限定名 org.apache.ibatis.type.TypeAliasRegistry#resolveAlias</span>
<span class="token keyword">public</span> <span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">T</span><span class="token punctuation">></span></span> <span class="token class-name">Class</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">T</span><span class="token punctuation">></span></span> <span class="token function">resolveAlias</span><span class="token punctuation">(</span><span class="token class-name">String</span> string<span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">try</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>string <span class="token operator">==</span> <span class="token keyword">null</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">return</span> <span class="token keyword">null</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token comment">// issue #748</span>
<span class="token class-name">String</span> key <span class="token operator">=</span> string<span class="token punctuation">.</span><span class="token function">toLowerCase</span><span class="token punctuation">(</span><span class="token class-name">Locale</span><span class="token punctuation">.</span><span class="token constant">ENGLISH</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token class-name">Class</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">T</span><span class="token punctuation">></span></span> value<span class="token punctuation">;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>typeAliases<span class="token punctuation">.</span><span class="token function">containsKey</span><span class="token punctuation">(</span>key<span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
value <span class="token operator">=</span> <span class="token punctuation">(</span><span class="token class-name">Class</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">T</span><span class="token punctuation">></span></span><span class="token punctuation">)</span> typeAliases<span class="token punctuation">.</span><span class="token function">get</span><span class="token punctuation">(</span>key<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span> <span class="token keyword">else</span> <span class="token punctuation">&#123;</span>
value <span class="token operator">=</span> <span class="token punctuation">(</span><span class="token class-name">Class</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">T</span><span class="token punctuation">></span></span><span class="token punctuation">)</span> <span class="token class-name">Resources</span><span class="token punctuation">.</span><span class="token function">classForName</span><span class="token punctuation">(</span>string<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token keyword">return</span> value<span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span> <span class="token keyword">catch</span> <span class="token punctuation">(</span><span class="token class-name">ClassNotFoundException</span> e<span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">throw</span> <span class="token keyword">new</span> <span class="token class-name">TypeException</span><span class="token punctuation">(</span><span class="token string">"Could not resolve type alias '"</span> <span class="token operator">+</span> string <span class="token operator">+</span> <span class="token string">"'. Cause: "</span> <span class="token operator">+</span> e<span class="token punctuation">,</span> e<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token punctuation">&#125;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>而通过JDBC获取得是啥的，就是在Configuration的构造方法里写了的JdbcTransactionFactory</p><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token keyword">public</span> <span class="token class-name">Configuration</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
typeAliasRegistry<span class="token punctuation">.</span><span class="token function">registerAlias</span><span class="token punctuation">(</span><span class="token string">"JDBC"</span><span class="token punctuation">,</span> <span class="token class-name">JdbcTransactionFactory</span><span class="token punctuation">.</span><span class="token keyword">class</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span></span></code></pre><p>所以我们在这</p><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token keyword">private</span> <span class="token class-name">SqlSession</span> <span class="token function">openSessionFromDataSource</span><span class="token punctuation">(</span><span class="token class-name">ExecutorType</span> execType<span class="token punctuation">,</span> <span class="token class-name">TransactionIsolationLevel</span> level<span class="token punctuation">,</span> <span class="token keyword">boolean</span> autoCommit<span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token class-name">Transaction</span> tx <span class="token operator">=</span> <span class="token keyword">null</span><span class="token punctuation">;</span>
<span class="token keyword">try</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">final</span> <span class="token class-name">Environment</span> environment <span class="token operator">=</span> configuration<span class="token punctuation">.</span><span class="token function">getEnvironment</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">final</span> <span class="token class-name">TransactionFactory</span> transactionFactory <span class="token operator">=</span> <span class="token function">getTransactionFactoryFromEnvironment</span><span class="token punctuation">(</span>environment<span class="token punctuation">)</span><span class="token punctuation">;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>获得到的TransactionFactory 就是 JdbcTransactionFactory ，而后</p><pre class="line-numbers language-java" data-language="java"><code class="language-java">tx <span class="token operator">=</span> transactionFactory<span class="token punctuation">.</span><span class="token function">newTransaction</span><span class="token punctuation">(</span>environment<span class="token punctuation">.</span><span class="token function">getDataSource</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">,</span> level<span class="token punctuation">,</span> autoCommit<span class="token punctuation">)</span><span class="token punctuation">;</span>
```java
创建的transaction就是<span class="token class-name">JdbcTransaction</span>
```java
<span class="token annotation punctuation">@Override</span>
<span class="token keyword">public</span> <span class="token class-name">Transaction</span> <span class="token function">newTransaction</span><span class="token punctuation">(</span><span class="token class-name">DataSource</span> ds<span class="token punctuation">,</span> <span class="token class-name">TransactionIsolationLevel</span> level<span class="token punctuation">,</span> <span class="token keyword">boolean</span> autoCommit<span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">return</span> <span class="token keyword">new</span> <span class="token class-name">JdbcTransaction</span><span class="token punctuation">(</span>ds<span class="token punctuation">,</span> level<span class="token punctuation">,</span> autoCommit<span class="token punctuation">,</span> skipSetAutoCommitOnClose<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>然后我们再会上去看代码getConnection ,</p><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token keyword">protected</span> <span class="token class-name">Connection</span> <span class="token function">getConnection</span><span class="token punctuation">(</span><span class="token class-name">Log</span> statementLog<span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">SQLException</span> <span class="token punctuation">&#123;</span>
<span class="token comment">// -------> 这里的transaction就是JdbcTransaction</span>
<span class="token class-name">Connection</span> connection <span class="token operator">=</span> transaction<span class="token punctuation">.</span><span class="token function">getConnection</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>statementLog<span class="token punctuation">.</span><span class="token function">isDebugEnabled</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">return</span> <span class="token class-name">ConnectionLogger</span><span class="token punctuation">.</span><span class="token function">newInstance</span><span class="token punctuation">(</span>connection<span class="token punctuation">,</span> statementLog<span class="token punctuation">,</span> queryStack<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span> <span class="token keyword">else</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">return</span> connection<span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token punctuation">&#125;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>即调用了</p><pre class="line-numbers language-java" data-language="java"><code class="language-java"> <span class="token annotation punctuation">@Override</span>
<span class="token keyword">public</span> <span class="token class-name">Connection</span> <span class="token function">getConnection</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">SQLException</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>connection <span class="token operator">==</span> <span class="token keyword">null</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token function">openConnection</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token keyword">return</span> connection<span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token keyword">protected</span> <span class="token keyword">void</span> <span class="token function">openConnection</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">SQLException</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>log<span class="token punctuation">.</span><span class="token function">isDebugEnabled</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
log<span class="token punctuation">.</span><span class="token function">debug</span><span class="token punctuation">(</span><span class="token string">"Opening JDBC Connection"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
connection <span class="token operator">=</span> dataSource<span class="token punctuation">.</span><span class="token function">getConnection</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>level <span class="token operator">!=</span> <span class="token keyword">null</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
connection<span class="token punctuation">.</span><span class="token function">setTransactionIsolation</span><span class="token punctuation">(</span>level<span class="token punctuation">.</span><span class="token function">getLevel</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token function">setDesiredAutoCommit</span><span class="token punctuation">(</span>autoCommit<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token annotation punctuation">@Override</span>
<span class="token keyword">public</span> <span class="token class-name">Connection</span> <span class="token function">getConnection</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">SQLException</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">return</span> <span class="token function">popConnection</span><span class="token punctuation">(</span>dataSource<span class="token punctuation">.</span><span class="token function">getUsername</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">,</span> dataSource<span class="token punctuation">.</span><span class="token function">getPassword</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">getProxyConnection</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token keyword">private</span> <span class="token class-name">PooledConnection</span> <span class="token function">popConnection</span><span class="token punctuation">(</span><span class="token class-name">String</span> username<span class="token punctuation">,</span> <span class="token class-name">String</span> password<span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">SQLException</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">boolean</span> countedWait <span class="token operator">=</span> <span class="token boolean">false</span><span class="token punctuation">;</span>
<span class="token class-name">PooledConnection</span> conn <span class="token operator">=</span> <span class="token keyword">null</span><span class="token punctuation">;</span>
<span class="token keyword">long</span> t <span class="token operator">=</span> <span class="token class-name">System</span><span class="token punctuation">.</span><span class="token function">currentTimeMillis</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">int</span> localBadConnectionCount <span class="token operator">=</span> <span class="token number">0</span><span class="token punctuation">;</span>
<span class="token keyword">while</span> <span class="token punctuation">(</span>conn <span class="token operator">==</span> <span class="token keyword">null</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
lock<span class="token punctuation">.</span><span class="token function">lock</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">try</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span><span class="token operator">!</span>state<span class="token punctuation">.</span>idleConnections<span class="token punctuation">.</span><span class="token function">isEmpty</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token comment">// Pool has available connection</span>
conn <span class="token operator">=</span> state<span class="token punctuation">.</span>idleConnections<span class="token punctuation">.</span><span class="token function">remove</span><span class="token punctuation">(</span><span class="token number">0</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>log<span class="token punctuation">.</span><span class="token function">isDebugEnabled</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
log<span class="token punctuation">.</span><span class="token function">debug</span><span class="token punctuation">(</span><span class="token string">"Checked out connection "</span> <span class="token operator">+</span> conn<span class="token punctuation">.</span><span class="token function">getRealHashCode</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator">+</span> <span class="token string">" from pool."</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token punctuation">&#125;</span> <span class="token keyword">else</span> <span class="token punctuation">&#123;</span>
<span class="token comment">// Pool does not have available connection</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>state<span class="token punctuation">.</span>activeConnections<span class="token punctuation">.</span><span class="token function">size</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator">&lt;</span> poolMaximumActiveConnections<span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token comment">// Can create new connection</span>
<span class="token comment">// ------------> 走到这里会创建PooledConnection，但是里面会先调用dataSource.getConnection()</span>
conn <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">PooledConnection</span><span class="token punctuation">(</span>dataSource<span class="token punctuation">.</span><span class="token function">getConnection</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">,</span> <span class="token keyword">this</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>log<span class="token punctuation">.</span><span class="token function">isDebugEnabled</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
log<span class="token punctuation">.</span><span class="token function">debug</span><span class="token punctuation">(</span><span class="token string">"Created connection "</span> <span class="token operator">+</span> conn<span class="token punctuation">.</span><span class="token function">getRealHashCode</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator">+</span> <span class="token string">"."</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token punctuation">&#125;</span> <span class="token keyword">else</span> <span class="token punctuation">&#123;</span>
<span class="token comment">// Cannot create new connection</span>
<span class="token class-name">PooledConnection</span> oldestActiveConnection <span class="token operator">=</span> state<span class="token punctuation">.</span>activeConnections<span class="token punctuation">.</span><span class="token function">get</span><span class="token punctuation">(</span><span class="token number">0</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">long</span> longestCheckoutTime <span class="token operator">=</span> oldestActiveConnection<span class="token punctuation">.</span><span class="token function">getCheckoutTime</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>longestCheckoutTime <span class="token operator">></span> poolMaximumCheckoutTime<span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token comment">// Can claim overdue connection</span>
state<span class="token punctuation">.</span>claimedOverdueConnectionCount<span class="token operator">++</span><span class="token punctuation">;</span>
state<span class="token punctuation">.</span>accumulatedCheckoutTimeOfOverdueConnections <span class="token operator">+=</span> longestCheckoutTime<span class="token punctuation">;</span>
state<span class="token punctuation">.</span>accumulatedCheckoutTime <span class="token operator">+=</span> longestCheckoutTime<span class="token punctuation">;</span>
state<span class="token punctuation">.</span>activeConnections<span class="token punctuation">.</span><span class="token function">remove</span><span class="token punctuation">(</span>oldestActiveConnection<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span><span class="token operator">!</span>oldestActiveConnection<span class="token punctuation">.</span><span class="token function">getRealConnection</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">getAutoCommit</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">try</span> <span class="token punctuation">&#123;</span>
oldestActiveConnection<span class="token punctuation">.</span><span class="token function">getRealConnection</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">rollback</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span> <span class="token keyword">catch</span> <span class="token punctuation">(</span><span class="token class-name">SQLException</span> e<span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token comment">/*
Just log a message for debug and continue to execute the following
statement like nothing happened.
Wrap the bad connection with a new PooledConnection, this will help
to not interrupt current executing thread and give current thread a
chance to join the next competition for another valid/good database
connection. At the end of this loop, bad &#123;@link @conn&#125; will be set as null.
*/</span>
log<span class="token punctuation">.</span><span class="token function">debug</span><span class="token punctuation">(</span><span class="token string">"Bad connection. Could not roll back"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token punctuation">&#125;</span>
conn <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">PooledConnection</span><span class="token punctuation">(</span>oldestActiveConnection<span class="token punctuation">.</span><span class="token function">getRealConnection</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">,</span> <span class="token keyword">this</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
conn<span class="token punctuation">.</span><span class="token function">setCreatedTimestamp</span><span class="token punctuation">(</span>oldestActiveConnection<span class="token punctuation">.</span><span class="token function">getCreatedTimestamp</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
conn<span class="token punctuation">.</span><span class="token function">setLastUsedTimestamp</span><span class="token punctuation">(</span>oldestActiveConnection<span class="token punctuation">.</span><span class="token function">getLastUsedTimestamp</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
oldestActiveConnection<span class="token punctuation">.</span><span class="token function">invalidate</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>log<span class="token punctuation">.</span><span class="token function">isDebugEnabled</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
log<span class="token punctuation">.</span><span class="token function">debug</span><span class="token punctuation">(</span><span class="token string">"Claimed overdue connection "</span> <span class="token operator">+</span> conn<span class="token punctuation">.</span><span class="token function">getRealHashCode</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator">+</span> <span class="token string">"."</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token punctuation">&#125;</span> <span class="token keyword">else</span> <span class="token punctuation">&#123;</span>
<span class="token comment">// Must wait</span>
<span class="token keyword">try</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span><span class="token operator">!</span>countedWait<span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
state<span class="token punctuation">.</span>hadToWaitCount<span class="token operator">++</span><span class="token punctuation">;</span>
countedWait <span class="token operator">=</span> <span class="token boolean">true</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>log<span class="token punctuation">.</span><span class="token function">isDebugEnabled</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
log<span class="token punctuation">.</span><span class="token function">debug</span><span class="token punctuation">(</span><span class="token string">"Waiting as long as "</span> <span class="token operator">+</span> poolTimeToWait <span class="token operator">+</span> <span class="token string">" milliseconds for connection."</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token keyword">long</span> wt <span class="token operator">=</span> <span class="token class-name">System</span><span class="token punctuation">.</span><span class="token function">currentTimeMillis</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
condition<span class="token punctuation">.</span><span class="token function">await</span><span class="token punctuation">(</span>poolTimeToWait<span class="token punctuation">,</span> <span class="token class-name">TimeUnit</span><span class="token punctuation">.</span><span class="token constant">MILLISECONDS</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
state<span class="token punctuation">.</span>accumulatedWaitTime <span class="token operator">+=</span> <span class="token class-name">System</span><span class="token punctuation">.</span><span class="token function">currentTimeMillis</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator">-</span> wt<span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span> <span class="token keyword">catch</span> <span class="token punctuation">(</span><span class="token class-name">InterruptedException</span> e<span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token comment">// set interrupt flag</span>
<span class="token class-name">Thread</span><span class="token punctuation">.</span><span class="token function">currentThread</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">interrupt</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">break</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token punctuation">&#125;</span>
<span class="token punctuation">&#125;</span>
<span class="token punctuation">&#125;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>conn <span class="token operator">!=</span> <span class="token keyword">null</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token comment">// ping to server and check the connection is valid or not</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>conn<span class="token punctuation">.</span><span class="token function">isValid</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span><span class="token operator">!</span>conn<span class="token punctuation">.</span><span class="token function">getRealConnection</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">getAutoCommit</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
conn<span class="token punctuation">.</span><span class="token function">getRealConnection</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">rollback</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
conn<span class="token punctuation">.</span><span class="token function">setConnectionTypeCode</span><span class="token punctuation">(</span><span class="token function">assembleConnectionTypeCode</span><span class="token punctuation">(</span>dataSource<span class="token punctuation">.</span><span class="token function">getUrl</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">,</span> username<span class="token punctuation">,</span> password<span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
conn<span class="token punctuation">.</span><span class="token function">setCheckoutTimestamp</span><span class="token punctuation">(</span><span class="token class-name">System</span><span class="token punctuation">.</span><span class="token function">currentTimeMillis</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
conn<span class="token punctuation">.</span><span class="token function">setLastUsedTimestamp</span><span class="token punctuation">(</span><span class="token class-name">System</span><span class="token punctuation">.</span><span class="token function">currentTimeMillis</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
state<span class="token punctuation">.</span>activeConnections<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span>conn<span class="token punctuation">)</span><span class="token punctuation">;</span>
state<span class="token punctuation">.</span>requestCount<span class="token operator">++</span><span class="token punctuation">;</span>
state<span class="token punctuation">.</span>accumulatedRequestTime <span class="token operator">+=</span> <span class="token class-name">System</span><span class="token punctuation">.</span><span class="token function">currentTimeMillis</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator">-</span> t<span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span> <span class="token keyword">else</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>log<span class="token punctuation">.</span><span class="token function">isDebugEnabled</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
log<span class="token punctuation">.</span><span class="token function">debug</span><span class="token punctuation">(</span><span class="token string">"A bad connection ("</span> <span class="token operator">+</span> conn<span class="token punctuation">.</span><span class="token function">getRealHashCode</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator">+</span> <span class="token string">") was returned from the pool, getting another connection."</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
state<span class="token punctuation">.</span>badConnectionCount<span class="token operator">++</span><span class="token punctuation">;</span>
localBadConnectionCount<span class="token operator">++</span><span class="token punctuation">;</span>
conn <span class="token operator">=</span> <span class="token keyword">null</span><span class="token punctuation">;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>localBadConnectionCount <span class="token operator">></span> <span class="token punctuation">(</span>poolMaximumIdleConnections <span class="token operator">+</span> poolMaximumLocalBadConnectionTolerance<span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>log<span class="token punctuation">.</span><span class="token function">isDebugEnabled</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
log<span class="token punctuation">.</span><span class="token function">debug</span><span class="token punctuation">(</span><span class="token string">"PooledDataSource: Could not get a good connection to the database."</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token keyword">throw</span> <span class="token keyword">new</span> <span class="token class-name">SQLException</span><span class="token punctuation">(</span><span class="token string">"PooledDataSource: Could not get a good connection to the database."</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token punctuation">&#125;</span>
<span class="token punctuation">&#125;</span>
<span class="token punctuation">&#125;</span> <span class="token keyword">finally</span> <span class="token punctuation">&#123;</span>
lock<span class="token punctuation">.</span><span class="token function">unlock</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token punctuation">&#125;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>conn <span class="token operator">==</span> <span class="token keyword">null</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>log<span class="token punctuation">.</span><span class="token function">isDebugEnabled</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
log<span class="token punctuation">.</span><span class="token function">debug</span><span class="token punctuation">(</span><span class="token string">"PooledDataSource: Unknown severe error condition. The connection pool returned a null connection."</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token keyword">throw</span> <span class="token keyword">new</span> <span class="token class-name">SQLException</span><span class="token punctuation">(</span><span class="token string">"PooledDataSource: Unknown severe error condition. The connection pool returned a null connection."</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token keyword">return</span> conn<span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>其实就是调用的</p><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token comment">// org.apache.ibatis.datasource.unpooled.UnpooledDataSource#getConnection()</span>
<span class="token annotation punctuation">@Override</span>
<span class="token keyword">public</span> <span class="token class-name">Connection</span> <span class="token function">getConnection</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">SQLException</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">return</span> <span class="token function">doGetConnection</span><span class="token punctuation">(</span>username<span class="token punctuation">,</span> password<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
```java
然后就是
```java
<span class="token keyword">private</span> <span class="token class-name">Connection</span> <span class="token function">doGetConnection</span><span class="token punctuation">(</span><span class="token class-name">String</span> username<span class="token punctuation">,</span> <span class="token class-name">String</span> password<span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">SQLException</span> <span class="token punctuation">&#123;</span>
<span class="token class-name">Properties</span> props <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">Properties</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>driverProperties <span class="token operator">!=</span> <span class="token keyword">null</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
props<span class="token punctuation">.</span><span class="token function">putAll</span><span class="token punctuation">(</span>driverProperties<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>username <span class="token operator">!=</span> <span class="token keyword">null</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
props<span class="token punctuation">.</span><span class="token function">setProperty</span><span class="token punctuation">(</span><span class="token string">"user"</span><span class="token punctuation">,</span> username<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>password <span class="token operator">!=</span> <span class="token keyword">null</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
props<span class="token punctuation">.</span><span class="token function">setProperty</span><span class="token punctuation">(</span><span class="token string">"password"</span><span class="token punctuation">,</span> password<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token keyword">return</span> <span class="token function">doGetConnection</span><span class="token punctuation">(</span>props<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>继续这个逻辑</p><pre class="line-numbers language-java" data-language="java"><code class="language-java"> <span class="token keyword">private</span> <span class="token class-name">Connection</span> <span class="token function">doGetConnection</span><span class="token punctuation">(</span><span class="token class-name">Properties</span> properties<span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">SQLException</span> <span class="token punctuation">&#123;</span>
<span class="token function">initializeDriver</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token class-name">Connection</span> connection <span class="token operator">=</span> <span class="token class-name">DriverManager</span><span class="token punctuation">.</span><span class="token function">getConnection</span><span class="token punctuation">(</span>url<span class="token punctuation">,</span> properties<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token function">configureConnection</span><span class="token punctuation">(</span>connection<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">return</span> connection<span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token annotation punctuation">@CallerSensitive</span>
<span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token class-name">Connection</span> <span class="token function">getConnection</span><span class="token punctuation">(</span><span class="token class-name">String</span> url<span class="token punctuation">,</span>
<span class="token class-name"><span class="token namespace">java<span class="token punctuation">.</span>util<span class="token punctuation">.</span></span>Properties</span> info<span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">SQLException</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">return</span> <span class="token punctuation">(</span><span class="token function">getConnection</span><span class="token punctuation">(</span>url<span class="token punctuation">,</span> info<span class="token punctuation">,</span> <span class="token class-name">Reflection</span><span class="token punctuation">.</span><span class="token function">getCallerClass</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token keyword">private</span> <span class="token keyword">static</span> <span class="token class-name">Connection</span> <span class="token function">getConnection</span><span class="token punctuation">(</span>
<span class="token class-name">String</span> url<span class="token punctuation">,</span> <span class="token class-name"><span class="token namespace">java<span class="token punctuation">.</span>util<span class="token punctuation">.</span></span>Properties</span> info<span class="token punctuation">,</span> <span class="token class-name">Class</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token operator">?</span><span class="token punctuation">></span></span> caller<span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">SQLException</span> <span class="token punctuation">&#123;</span>
<span class="token comment">/*
* When callerCl is null, we should check the application's
* (which is invoking this class indirectly)
* classloader, so that the JDBC driver class outside rt.jar
* can be loaded from here.
*/</span>
<span class="token class-name">ClassLoader</span> callerCL <span class="token operator">=</span> caller <span class="token operator">!=</span> <span class="token keyword">null</span> <span class="token operator">?</span> caller<span class="token punctuation">.</span><span class="token function">getClassLoader</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator">:</span> <span class="token keyword">null</span><span class="token punctuation">;</span>
<span class="token keyword">synchronized</span><span class="token punctuation">(</span><span class="token class-name">DriverManager</span><span class="token punctuation">.</span><span class="token keyword">class</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token comment">// synchronize loading of the correct classloader.</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>callerCL <span class="token operator">==</span> <span class="token keyword">null</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
callerCL <span class="token operator">=</span> <span class="token class-name">Thread</span><span class="token punctuation">.</span><span class="token function">currentThread</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">getContextClassLoader</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token punctuation">&#125;</span>
<span class="token keyword">if</span><span class="token punctuation">(</span>url <span class="token operator">==</span> <span class="token keyword">null</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">throw</span> <span class="token keyword">new</span> <span class="token class-name">SQLException</span><span class="token punctuation">(</span><span class="token string">"The url cannot be null"</span><span class="token punctuation">,</span> <span class="token string">"08001"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token function">println</span><span class="token punctuation">(</span><span class="token string">"DriverManager.getConnection(\""</span> <span class="token operator">+</span> url <span class="token operator">+</span> <span class="token string">"\")"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token comment">// Walk through the loaded registeredDrivers attempting to make a connection.</span>
<span class="token comment">// Remember the first exception that gets raised so we can reraise it.</span>
<span class="token class-name">SQLException</span> reason <span class="token operator">=</span> <span class="token keyword">null</span><span class="token punctuation">;</span>
<span class="token keyword">for</span><span class="token punctuation">(</span><span class="token class-name">DriverInfo</span> aDriver <span class="token operator">:</span> registeredDrivers<span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token comment">// If the caller does not have permission to load the driver then</span>
<span class="token comment">// skip it.</span>
<span class="token keyword">if</span><span class="token punctuation">(</span><span class="token function">isDriverAllowed</span><span class="token punctuation">(</span>aDriver<span class="token punctuation">.</span>driver<span class="token punctuation">,</span> callerCL<span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">try</span> <span class="token punctuation">&#123;</span>
<span class="token comment">// ----------> driver[className=com.mysql.cj.jdbc.Driver@64030b91]</span>
<span class="token function">println</span><span class="token punctuation">(</span><span class="token string">" trying "</span> <span class="token operator">+</span> aDriver<span class="token punctuation">.</span>driver<span class="token punctuation">.</span><span class="token function">getClass</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">getName</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token class-name">Connection</span> con <span class="token operator">=</span> aDriver<span class="token punctuation">.</span>driver<span class="token punctuation">.</span><span class="token function">connect</span><span class="token punctuation">(</span>url<span class="token punctuation">,</span> info<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>con <span class="token operator">!=</span> <span class="token keyword">null</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token comment">// Success!</span>
<span class="token function">println</span><span class="token punctuation">(</span><span class="token string">"getConnection returning "</span> <span class="token operator">+</span> aDriver<span class="token punctuation">.</span>driver<span class="token punctuation">.</span><span class="token function">getClass</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">getName</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">return</span> <span class="token punctuation">(</span>con<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token punctuation">&#125;</span> <span class="token keyword">catch</span> <span class="token punctuation">(</span><span class="token class-name">SQLException</span> ex<span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>reason <span class="token operator">==</span> <span class="token keyword">null</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
reason <span class="token operator">=</span> ex<span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token punctuation">&#125;</span>
<span class="token punctuation">&#125;</span> <span class="token keyword">else</span> <span class="token punctuation">&#123;</span>
<span class="token function">println</span><span class="token punctuation">(</span><span class="token string">" skipping: "</span> <span class="token operator">+</span> aDriver<span class="token punctuation">.</span><span class="token function">getClass</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">getName</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token punctuation">&#125;</span>
<span class="token comment">// if we got here nobody could connect.</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span>reason <span class="token operator">!=</span> <span class="token keyword">null</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token function">println</span><span class="token punctuation">(</span><span class="token string">"getConnection failed: "</span> <span class="token operator">+</span> reason<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">throw</span> reason<span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token function">println</span><span class="token punctuation">(</span><span class="token string">"getConnection: no suitable driver found for "</span><span class="token operator">+</span> url<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">throw</span> <span class="token keyword">new</span> <span class="token class-name">SQLException</span><span class="token punctuation">(</span><span class="token string">"No suitable driver found for "</span><span class="token operator">+</span> url<span class="token punctuation">,</span> <span class="token string">"08001"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>上面的driver就是driver[className&#x3D;com.mysql.cj.jdbc.Driver@64030b91]</p><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token comment">// com.mysql.cj.jdbc.NonRegisteringDriver#connect</span>
<span class="token keyword">public</span> <span class="token class-name">Connection</span> <span class="token function">connect</span><span class="token punctuation">(</span><span class="token class-name">String</span> url<span class="token punctuation">,</span> <span class="token class-name">Properties</span> info<span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">SQLException</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">try</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">try</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span><span class="token operator">!</span><span class="token class-name">ConnectionUrl</span><span class="token punctuation">.</span><span class="token function">acceptsUrl</span><span class="token punctuation">(</span>url<span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">return</span> <span class="token keyword">null</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span> <span class="token keyword">else</span> <span class="token punctuation">&#123;</span>
<span class="token class-name">ConnectionUrl</span> conStr <span class="token operator">=</span> <span class="token class-name">ConnectionUrl</span><span class="token punctuation">.</span><span class="token function">getConnectionUrlInstance</span><span class="token punctuation">(</span>url<span class="token punctuation">,</span> info<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">switch</span> <span class="token punctuation">(</span>conStr<span class="token punctuation">.</span><span class="token function">getType</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">case</span> <span class="token constant">SINGLE_CONNECTION</span><span class="token operator">:</span>
<span class="token keyword">return</span> <span class="token class-name">ConnectionImpl</span><span class="token punctuation">.</span><span class="token function">getInstance</span><span class="token punctuation">(</span>conStr<span class="token punctuation">.</span><span class="token function">getMainHost</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">case</span> <span class="token constant">FAILOVER_CONNECTION</span><span class="token operator">:</span>
<span class="token keyword">case</span> <span class="token constant">FAILOVER_DNS_SRV_CONNECTION</span><span class="token operator">:</span>
<span class="token keyword">return</span> <span class="token class-name">FailoverConnectionProxy</span><span class="token punctuation">.</span><span class="token function">createProxyInstance</span><span class="token punctuation">(</span>conStr<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">case</span> <span class="token constant">LOADBALANCE_CONNECTION</span><span class="token operator">:</span>
<span class="token keyword">case</span> <span class="token constant">LOADBALANCE_DNS_SRV_CONNECTION</span><span class="token operator">:</span>
<span class="token keyword">return</span> <span class="token class-name">LoadBalancedConnectionProxy</span><span class="token punctuation">.</span><span class="token function">createProxyInstance</span><span class="token punctuation">(</span>conStr<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">case</span> <span class="token constant">REPLICATION_CONNECTION</span><span class="token operator">:</span>
<span class="token keyword">case</span> <span class="token constant">REPLICATION_DNS_SRV_CONNECTION</span><span class="token operator">:</span>
<span class="token keyword">return</span> <span class="token class-name">ReplicationConnectionProxy</span><span class="token punctuation">.</span><span class="token function">createProxyInstance</span><span class="token punctuation">(</span>conStr<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">default</span><span class="token operator">:</span>
<span class="token keyword">return</span> <span class="token keyword">null</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token punctuation">&#125;</span>
<span class="token punctuation">&#125;</span> <span class="token keyword">catch</span> <span class="token punctuation">(</span><span class="token class-name">UnsupportedConnectionStringException</span> var5<span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">return</span> <span class="token keyword">null</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span> <span class="token keyword">catch</span> <span class="token punctuation">(</span><span class="token class-name">CJException</span> var6<span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">throw</span> <span class="token punctuation">(</span><span class="token class-name">UnableToConnectException</span><span class="token punctuation">)</span><span class="token class-name">ExceptionFactory</span><span class="token punctuation">.</span><span class="token function">createException</span><span class="token punctuation">(</span><span class="token class-name">UnableToConnectException</span><span class="token punctuation">.</span><span class="token keyword">class</span><span class="token punctuation">,</span> <span class="token class-name">Messages</span><span class="token punctuation">.</span><span class="token function">getString</span><span class="token punctuation">(</span><span class="token string">"NonRegisteringDriver.17"</span><span class="token punctuation">,</span> <span class="token keyword">new</span> <span class="token class-name">Object</span><span class="token punctuation">[</span><span class="token punctuation">]</span><span class="token punctuation">&#123;</span>var6<span class="token punctuation">.</span><span class="token function">toString</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">&#125;</span><span class="token punctuation">)</span><span class="token punctuation">,</span> var6<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token punctuation">&#125;</span> <span class="token keyword">catch</span> <span class="token punctuation">(</span><span class="token class-name">CJException</span> var7<span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">throw</span> <span class="token class-name">SQLExceptionsMapping</span><span class="token punctuation">.</span><span class="token function">translateException</span><span class="token punctuation">(</span>var7<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>
<span class="token punctuation">&#125;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>这是个 SINGLE_CONNECTION ,所以调用的就是 return ConnectionImpl.getInstance(conStr.getMainHost());<br>然后在这里设置了代理类</p><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token keyword">public</span> <span class="token class-name">PooledConnection</span><span class="token punctuation">(</span><span class="token class-name">Connection</span> connection<span class="token punctuation">,</span> <span class="token class-name">PooledDataSource</span> dataSource<span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">this</span><span class="token punctuation">.</span>hashCode <span class="token operator">=</span> connection<span class="token punctuation">.</span><span class="token function">hashCode</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">this</span><span class="token punctuation">.</span>realConnection <span class="token operator">=</span> connection<span class="token punctuation">;</span>
<span class="token keyword">this</span><span class="token punctuation">.</span>dataSource <span class="token operator">=</span> dataSource<span class="token punctuation">;</span>
<span class="token keyword">this</span><span class="token punctuation">.</span>createdTimestamp <span class="token operator">=</span> <span class="token class-name">System</span><span class="token punctuation">.</span><span class="token function">currentTimeMillis</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">this</span><span class="token punctuation">.</span>lastUsedTimestamp <span class="token operator">=</span> <span class="token class-name">System</span><span class="token punctuation">.</span><span class="token function">currentTimeMillis</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">this</span><span class="token punctuation">.</span>valid <span class="token operator">=</span> <span class="token boolean">true</span><span class="token punctuation">;</span>
<span class="token keyword">this</span><span class="token punctuation">.</span>proxyConnection <span class="token operator">=</span> <span class="token punctuation">(</span><span class="token class-name">Connection</span><span class="token punctuation">)</span> <span class="token class-name">Proxy</span><span class="token punctuation">.</span><span class="token function">newProxyInstance</span><span class="token punctuation">(</span><span class="token class-name">Connection</span><span class="token punctuation">.</span><span class="token keyword">class</span><span class="token punctuation">.</span><span class="token function">getClassLoader</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">,</span> <span class="token constant">IFACES</span><span class="token punctuation">,</span> <span class="token keyword">this</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre><p>结合这个</p><pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token annotation punctuation">@Override</span>
<span class="token keyword">public</span> <span class="token class-name">Connection</span> <span class="token function">getConnection</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">SQLException</span> <span class="token punctuation">&#123;</span>
<span class="token keyword">return</span> <span class="token function">popConnection</span><span class="token punctuation">(</span>dataSource<span class="token punctuation">.</span><span class="token function">getUsername</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">,</span> dataSource<span class="token punctuation">.</span><span class="token function">getPassword</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">getProxyConnection</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span></span></code></pre><p>所以最终的connection就是com.mysql.cj.jdbc.ConnectionImpl@358ab600</p></div><footer class="post-footer"><div class="post-eof"></div></footer></article></div><nav class="pagination"><span class="page-number current">1</span><a class="page-number" href="/page/2/">2</a><span class="space">&hellip;</span><a class="page-number" href="/page/39/">39</a><a class="extend next" rel="next" title="下一页" aria-label="下一页" href="/page/2/"><i class="fa fa-angle-right"></i></a></nav></div></main><footer class="footer"><div class="footer-inner"><div class="beian"><a href="https://beian.miit.gov.cn/" rel="noopener" target="_blank">浙ICP备16002580号-2 </a><img src="/uploads/beian.png" alt=""><a href="http://www.beian.gov.cn/portal/registerSystemInfo?recordcode=33010602011094" rel="noopener" target="_blank">浙公网安备 33010602011094号</a></div><div class="copyright">&copy; 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