https://Orangex-position0.github.io/tags/interview/Recent content in Interview on Orangex-position0的技术博客Hugo -- gohugo.iozh-cnMon, 16 Mar 2026 14:00:00 +0800https://Orangex-position0.github.io/posts/computer-fundamentals/os-basics/Mon, 16 Mar 2026 14:00:00 +0800https://Orangex-position0.github.io/posts/computer-fundamentals/os-basics/<h2 id="进程-process"><a href="#%e8%bf%9b%e7%a8%8b-process" class="header-anchor"></a>进程 (Process) </h2><p>进程是操作系统分配资源的基本单位。</p> <h3 id="进程特征"><a href="#%e8%bf%9b%e7%a8%8b%e7%89%b9%e5%be%81" class="header-anchor"></a>进程特征 </h3><ul> <li>独立性：拥有独立的内存空间</li> <li>动态性：动态创建、运行、消亡</li> <li>并发性：多个进程可以并发执行</li> </ul> <h3 id="进程状态转换"><a href="#%e8%bf%9b%e7%a8%8b%e7%8a%b6%e6%80%81%e8%bd%ac%e6%8d%a2" class="header-anchor"></a>进程状态转换 </h3><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-fallback" data-lang="fallback"><span class="line"><span class="cl">就绪 → 运行 → 阻塞 </span></span><span class="line"><span class="cl"> ↑ ↓ </span></span><span class="line"><span class="cl"> ←———————←—————— </span></span></code></pre></div><h2 id="线程-thread"><a href="#%e7%ba%bf%e7%a8%8b-thread" class="header-anchor"></a>线程 (Thread) </h2><p>线程是 CPU 调度的基本单位，轻量级进程（LWP）。</p> <h3 id="线程特点"><a href="#%e7%ba%bf%e7%a8%8b%e7%89%b9%e7%82%b9" class="header-anchor"></a>线程特点 </h3><ul> <li>共享进程资源（内存、文件等）</li> <li>独立的执行流（寄存器、栈）</li> <li>创建和切换开销小</li> </ul> <h2 id="进程-vs-线程"><a href="#%e8%bf%9b%e7%a8%8b-vs-%e7%ba%bf%e7%a8%8b" class="header-anchor"></a>进程 vs 线程 </h2><table> <thead> <tr> <th>特性</th> <th>进程</th> <th>线程</th> </tr> </thead> <tbody> <tr> <td>资源共享</td> <td>独立</td> <td>共享</td> </tr> <tr> <td>通信方式</td> <td>IPC（管道、消息队列等）</td> <td>共享内存</td> </tr> <tr> <td>开销</td> <td>大</td> <td>小</td> </tr> <tr> <td>安全性</td> <td>高（隔离）</td> <td>低（需同步）</td> </tr> </tbody> </table> <h2 id="总结"><a href="#%e6%80%bb%e7%bb%93" class="header-anchor"></a>总结 </h2><ul> <li>进程是资源分配单位</li> <li>线程是调度执行单位</li> <li>现代应用通常采用多线程模型提高并发性能</li> </ul>https://Orangex-position0.github.io/posts/java/concurrent-hashmap/Mon, 16 Mar 2026 11:05:04 +0800https://Orangex-position0.github.io/posts/java/concurrent-hashmap/<h2 id="概述"><a href="#%e6%a6%82%e8%bf%b0" class="header-anchor"></a>概述 </h2><p><code>ConcurrentHashMap</code> 是 Java 并发包中最重要的并发容器之一，本文将深入分析其实现原理。</p> <h2 id="核心特点"><a href="#%e6%a0%b8%e5%bf%83%e7%89%b9%e7%82%b9" class="header-anchor"></a>核心特点 </h2><ol> <li><strong>线程安全</strong>：无需额外同步措施即可在多线程环境下使用</li> <li><strong>高性能</strong>：采用分段锁/ CAS 机制，减少锁竞争</li> <li><strong>弱一致性</strong>：迭代器不保证强一致性，但不会抛出 <code>ConcurrentModificationException</code></li> </ol> <h2 id="jdk-17-实现分段锁"><a href="#jdk-17-%e5%ae%9e%e7%8e%b0%e5%88%86%e6%ae%b5%e9%94%81" class="header-anchor"></a>JDK 1.7 实现：分段锁 </h2><h3 id="segment-结构"><a href="#segment-%e7%bb%93%e6%9e%84" class="header-anchor"></a>Segment 结构 </h3><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-java" data-lang="java"><span class="line"><span class="cl"><span class="kd">static</span><span class="w"> </span><span class="kd">final</span><span class="w"> </span><span class="kd">class</span> <span class="nc">Segment</span><span class="o">&lt;</span><span class="n">K</span><span class="p">,</span><span class="n">V</span><span class="o">&gt;</span><span class="w"> </span><span class="kd">extends</span><span class="w"> </span><span class="n">ReentrantLock</span><span class="w"> </span><span class="p">{</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="kd">transient</span><span class="w"> </span><span class="kd">volatile</span><span class="w"> </span><span class="n">HashEntry</span><span class="o">&lt;</span><span class="n">K</span><span class="p">,</span><span class="n">V</span><span class="o">&gt;[]</span><span class="w"> </span><span class="n">table</span><span class="p">;</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="c1">// ...</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="p">}</span><span class="w"> </span></span></span></code></pre></div><h2 id="jdk-18-实现cas--synchronized"><a href="#jdk-18-%e5%ae%9e%e7%8e%b0cas--synchronized" class="header-anchor"></a>JDK 1.8 实现：CAS + synchronized </h2><h3 id="核心改进"><a href="#%e6%a0%b8%e5%bf%83%e6%94%b9%e8%bf%9b" class="header-anchor"></a>核心改进 </h3><ul> <li>取消 Segment 分段，直接使用 Node 数组</li> <li>使用 CAS + synchronized 实现更细粒度的锁</li> <li>红黑树优化链表过长问题</li> </ul> <h2 id="总结"><a href="#%e6%80%bb%e7%bb%93" class="header-anchor"></a>总结 </h2><p>ConcurrentHashMap 的演进体现了 Java 在并发领域的持续优化。</p>