https://axerzone.cn/tags/%E9%9B%86%E5%90%88%E6%A1%86%E6%9E%B6/Recent content in 集合框架 on Weiming's BlogHugo -- gohugo.iozh-cn© 2026 WeimingSun, 20 Nov 2022 00:00:00 +0000https://axerzone.cn/posts/concurrenthashmap-deep-dive/Sun, 20 Nov 2022 00:00:00 +0000https://axerzone.cn/posts/concurrenthashmap-deep-dive/<h1 class="relative group">ConcurrentHashMap 到底怎么保证线程安全的 <div id="concurrenthashmap-到底怎么保证线程安全的" class="anchor"></div> <span class="absolute top-0 w-6 transition-opacity opacity-0 -start-6 not-prose group-hover:opacity-100 select-none"> <a class="text-primary-300 dark:text-neutral-700 !no-underline" href="#concurrenthashmap-%e5%88%b0%e5%ba%95%e6%80%8e%e4%b9%88%e4%bf%9d%e8%af%81%e7%ba%bf%e7%a8%8b%e5%ae%89%e5%85%a8%e7%9a%84" aria-label="锚点">#</a> </span> </h1> <p>上篇写了 HashMap，有同学私信问我 ConcurrentHashMap 和 HashMap 有什么区别。其实吧，区别大了去了，JDK8 的 ConcurrentHashMap 基本是重写的，跟 JDK7 完全两个思路。</p> <p>花了差不多一周把源码理清楚，这篇来聊聊它到底怎么在并发场景下保证线程安全。</p> <h2 class="relative group">JDK7 的 Segment 分段锁 <div id="jdk7-的-segment-分段锁" class="anchor"></div> <span class="absolute top-0 w-6 transition-opacity opacity-0 -start-6 not-prose group-hover:opacity-100 select-none"> <a class="text-primary-300 dark:text-neutral-700 !no-underline" href="#jdk7-%e7%9a%84-segment-%e5%88%86%e6%ae%b5%e9%94%81" aria-label="锚点">#</a> </span> </h2> <p>先说 JDK7 的方案，面试还是会问。</p>https://axerzone.cn/posts/hashmap-source-code/Thu, 15 Sep 2022 00:00:00 +0000https://axerzone.cn/posts/hashmap-source-code/<h1 class="relative group">HashMap 源码我读了三遍才看懂 <div id="hashmap-源码我读了三遍才看懂" class="anchor"></div> <span class="absolute top-0 w-6 transition-opacity opacity-0 -start-6 not-prose group-hover:opacity-100 select-none"> <a class="text-primary-300 dark:text-neutral-700 !no-underline" href="#hashmap-%e6%ba%90%e7%a0%81%e6%88%91%e8%af%bb%e4%ba%86%e4%b8%89%e9%81%8d%e6%89%8d%e7%9c%8b%e6%87%82" aria-label="锚点">#</a> </span> </h1> <p>大二下学期面试实习的时候，面试官问我 HashMap 的底层原理，我支支吾吾说了个&quot;数组加链表&quot;就说不下去了。回来之后就下定决心要把源码读一遍。结果读了三遍才算真正搞明白，这玩意比我想象的要精妙得多。</p> <p><figure><img class="my-0 rounded-md" loading="lazy" decoding="async" fetchpriority="low" alt="Hash Table 示意图" src="https://upload.wikimedia.org/wikipedia/commons/thumb/5/5e/Hash_table_5_0_1_1_1_1_0_SP.svg/380px-Hash_table_5_0_1_1_1_1_0_SP.svg.png" ></figure> </p> <h2 class="relative group">先说说 HashMap 的内部结构 <div id="先说说-hashmap-的内部结构" class="anchor"></div> <span class="absolute top-0 w-6 transition-opacity opacity-0 -start-6 not-prose group-hover:opacity-100 select-none"> <a class="text-primary-300 dark:text-neutral-700 !no-underline" href="#%e5%85%88%e8%af%b4%e8%af%b4-hashmap-%e7%9a%84%e5%86%85%e9%83%a8%e7%bb%93%e6%9e%84" aria-label="锚点">#</a> </span> </h2> <p>你打开 HashMap 的源码，会看到一个叫 <code>Node&lt;K,V&gt;[] table</code> 的数组。这就是 HashMap 的骨架。</p>