https://wang-xu-97.github.io/nayun.github.io/tags/%E6%A6%82%E5%BF%B5/Recent content in 概念 on nayun blogHugo -- gohugo.iozh-cn© 2026 nayunFri, 25 Jul 2025 16:08:19 +0800https://wang-xu-97.github.io/nayun.github.io/tech/coding/python/%E6%A6%82%E5%BF%B5%E5%9F%BA%E7%A1%80/%E5%85%83%E7%B1%BBmetaclass/Fri, 25 Jul 2025 16:08:19 +0800https://wang-xu-97.github.io/nayun.github.io/tech/coding/python/%E6%A6%82%E5%BF%B5%E5%9F%BA%E7%A1%80/%E5%85%83%E7%B1%BBmetaclass/<p>元类作用时机<br> 当使用此元类定义新类时（如 class MyClass(metaclass=StaticMethodMeta)），元类的 <code>__new__</code> 方法会在类创建时被调用。</p> <p>利用元类改变类特性 -&gt; 创建一个成员函数自动转换为静态成员函数的类</p> <div class="code-block-wrapper"> <div class="code-header"> <span class="language-label"> <span class="language-brackets">&lt;/></span> <span class="language-name">python</span> </span> <div class="code-buttons"> <button class="copy-button"> <i class="fas fa-copy"></i> <span>复制</span> </button> </div> </div> <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-python" data-lang="python"><span class="line"><span class="ln"> 1</span><span class="cl"><span class="k">class</span> <span class="nc">StaticMethodMeta</span><span class="p">(</span><span class="nb">type</span><span class="p">):</span> </span></span><span class="line"><span class="ln"> 2</span><span class="cl"> <span class="k">def</span> <span class="fm">__new__</span><span class="p">(</span><span class="bp">cls</span><span class="p">,</span> <span class="n">name</span><span class="p">,</span> <span class="n">bases</span><span class="p">,</span> <span class="n">namespace</span><span class="p">):</span> </span></span><span class="line"><span class="ln"> 3</span><span class="cl"> <span class="k">for</span> <span class="n">attr_name</span><span class="p">,</span> <span class="n">attr_value</span> <span class="ow">in</span> <span class="n">namespace</span><span class="o">.</span><span class="n">items</span><span class="p">():</span> </span></span><span class="line"><span class="ln"> 4</span><span class="cl"> <span class="k">if</span> <span class="n">callable</span><span class="p">(</span><span class="n">attr_value</span><span class="p">)</span> <span class="ow">and</span> <span class="ow">not</span> <span class="n">attr_name</span><span class="o">.</span><span class="n">startswith</span><span class="p">(</span><span class="s1">&#39;__&#39;</span><span class="p">):</span> </span></span><span class="line"><span class="ln"> 5</span><span class="cl"> <span class="n">namespace</span><span class="p">[</span><span class="n">attr_name</span><span class="p">]</span> <span class="o">=</span> <span class="nb">staticmethod</span><span class="p">(</span><span class="n">attr_value</span><span class="p">)</span> </span></span><span class="line"><span class="ln"> 6</span><span class="cl"> <span class="k">return</span> <span class="nb">super</span><span class="p">()</span><span class="o">.</span><span class="fm">__new__</span><span class="p">(</span><span class="bp">cls</span><span class="p">,</span> <span class="n">name</span><span class="p">,</span> <span class="n">bases</span><span class="p">,</span> <span class="n">namespace</span><span class="p">)</span> </span></span><span class="line"><span class="ln"> 7</span><span class="cl"> </span></span><span class="line"><span class="ln"> 8</span><span class="cl"><span class="k">class</span> <span class="nc">tool</span><span class="p">(</span><span class="n">metaclass</span><span class="o">=</span><span class="n">StaticMethodMeta</span><span class="p">):</span> </span></span><span class="line"><span class="ln"> 9</span><span class="cl"> <span class="c1"># 静态成员没有self参数</span> </span></span><span class="line"><span class="ln">10</span><span class="cl"> <span class="k">def</span> <span class="nf">tool1</span><span class="p">(</span><span class="n">p1</span><span class="p">,</span> <span class="n">p2</span><span class="p">):</span> </span></span><span class="line"><span class="ln">11</span><span class="cl"> <span class="k">pass</span></span></span></code></pre></div> </div>