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玩转spring之Singleton（单例模式）
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<h5 id="Singleton模式简介"><a href="#Singleton模式简介" class="headerlink" title="Singleton模式简介"></a>Singleton模式简介</h5><p>1.单例模式是我们编程中使用最广泛的设计模式之一，作用就是保证在应用中，一个类只有一个实例存在 </p>
<p>2.单例模式有三个特点 </p>
<ul>
<li>该类只有一个实例 </li>
<li>该类自行创建该实例（在该类内部创建自身的实例对象） <a id="more"></a></li>
<li>向整个系统公开这个实例接口 </li>
</ul>
<h5 id="Singleton模式的简单实现"><a href="#Singleton模式的简单实现" class="headerlink" title="Singleton模式的简单实现"></a>Singleton模式的简单实现</h5><p>1.最简单的单例实现方法，即将构造方法私有化，在类的内部创建该类的唯一实例，然后提供一个静态方法作为获取该实例的接口，犹如以下代码<br><img src="/images/simple_singleton.png" alt></p>
<p>2.则该Singleton类的实例可以通过如下这句代码获得 </p>
<p><img src="/images/simple_singleton_get_code.png" alt></p>
<p>3.上面的单例实现方式会在Singleton类加载的时候立即初始化一个实例，称为饿汉式加载。但对于资源开销比较大的类，更适合的做法是将实例化推迟到第一次使用它的时候，即懒汉式加载（惰性加载），比如以下代码 </p>
<p><img src="/images/lazy_singleton.png" alt></p>
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<li><strong>本文标题：</strong><a href="https://blog.visutech.cn/44388.html">玩转spring之Singleton（单例模式）</a></li>
<li><strong>本文作者：</strong><a href="https://blog.visutech.cn">程振奇 | smallodd</a></li>
<li><strong>本文链接：</strong><a href="https://blog.visutech.cn/44388.html">https://blog.visutech.cn/44388.html</a></li>
<li><strong>发布时间：</strong>2014-02-09</li>
<li><strong>版权声明：</strong>本博客所有文章除特别声明外，均采用 <a href="https://creativecommons.org/licenses/by-nc-sa/4.0/deed.zh" rel="external nofollow" target="_blank">CC BY-NC-SA 4.0</a> 许可协议。转载请注明出处！
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