spring 项目加载完立刻执行

来源：互联网发布：最完美的丁丁长度知乎编辑：程序博客网时间：2024/05/18 00:08

我的目的是想在项目加载完毕之后,需要进行一些初始化的动作,比如从数据库查询数据,缓存起来.

找到了三种方式:

第一种方式
写一个类，实现BeanPostProcessor，这个接口有两个方法
（1）postProcessBeforeInitialization方法，在spring中定义的bean初始化前调用这个方法；
（2）postProcessAfterInitialization方法，在spring中定义的bean初始化后调用这个方法；
这个虽然也能执行,但是是每次加载一个bean都会去执行,不太满足我的要求,我只需要一次就ok了,但是这个接口针对某个专门的bean有用
第二种方式编写一个实现ApplicationListener的listener类

<code class="hljs axapta has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">@Service<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">StartupListener</span> <span class="hljs-inheritance" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">implements</span></span>           <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">ApplicationListener</span><<span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">ContextRefreshedEvent</span> > {</span>      <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> String ShopNum ;      @Autowired      ShopService shopService;      @Override      <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> onApplicationEvent(ContextRefreshedEvent event) {           <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> ( event.getApplicationContext (). getParent() == <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">null</span>) {               <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// TODO 这里写下将要初始化的内容</span>               Shop shopByShopNum = shopService                         .getShopByShopNum (<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"e7-80-2e-e8-6c-a6"</span> );                System.out .println (<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"----------------------------"</span> );           } }}</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li></ul><div class="save_code tracking-ad" data-mod="popu_249" style="box-sizing: border-box; position: absolute; height: 60px; right: 30px; top: 5px; color: rgb(255, 255, 255); cursor: pointer; z-index: 2;"><a target=_blank target="_blank" style="color: rgb(51, 102, 153); box-sizing: border-box;"><img src="http://static.blog.csdn.net/images/save_snippets.png" style="border: none; box-sizing: border-box; max-width: 100%;" alt="" /></a></div>

亲测可用,但是我这个项目用不了,是项目比较特殊,加载了两次spring MV容器,导致执行两次,.

最后一种方式编写InitializingBean的实现类

<code class="hljs java has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Service</span><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">Test</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">implements</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">InitializingBean</span>{</span>      <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Autowired</span>      ShopService shopService;      <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>      <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">afterPropertiesSet</span>() <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">throws</span> Exception {           Shop shopByShopNum = shopService.getShopByShopNum( <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"e7-80-2e-e8-6c-a6"</span>);           System.out .println (<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"----------------------------"</span> );      }}</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li></ul>

项目在加载完毕后立刻执行afterPropertiesSet 方法 ,并且可以使用spring 注入好的bean

4.第四种就是servlet,但是他不能使用spring 的bean 还需要手动获取,比较麻烦.

原文:http://blog.csdn.net/liuyifeng1920/article/details/49800537

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