http://www.wfcoding.com/tags/%E4%BE%9D%E8%B5%96%E6%B3%A8%E5%85%A5/ Recent content in 依赖注入 on 有趣的AI Hugo -- 0.164.0 zh-CN 火云 Fri, 07 Aug 2026 00:00:00 +0000 http://www.wfcoding.com/articles/design/0107/ Fri, 07 Aug 2026 00:00:00 +0000 http://www.wfcoding.com/articles/design/0107/ <p>AI 写代码时，非常喜欢一种“最快能跑”的方式,，例如：</p> <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-python" data-lang="python"><span class="line"><span class="cl"><span class="n">db</span> <span class="o">=</span> <span class="n">Database</span><span class="p">()</span> </span></span><span class="line"><span class="cl"><span class="n">cache</span> <span class="o">=</span> <span class="n">RedisCache</span><span class="p">()</span> </span></span><span class="line"><span class="cl"><span class="n">mailer</span> <span class="o">=</span> <span class="n">EmailService</span><span class="p">()</span> </span></span><span class="line"><span class="cl"><span class="n">service</span> <span class="o">=</span> <span class="n">UserService</span><span class="p">()</span> </span></span></code></pre></div><p>哪里需要，就在哪里创建。</p> <p>短期看很方便，但当项目越来越大以后，就会出现：</p> <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-text" data-lang="text"><span class="line"><span class="cl">数据库实例到处创建 </span></span><span class="line"><span class="cl">缓存客户端到处创建 </span></span><span class="line"><span class="cl">配置散落 </span></span><span class="line"><span class="cl">Service 互相 new </span></span><span class="line"><span class="cl">测试时无法替换依赖 </span></span></code></pre></div><p>这类代码最明显的问题是：</p> <blockquote> <p><strong>对象把自己的依赖写死了。</strong></p> </blockquote> <p>而 <strong>DI（Dependency Injection，依赖注入）</strong> 要解决的，就是这件事。</p> <hr>