spring加载完bean之后执行相关初始化

spring是j2ee比较常用的开源技术，集成spring只需在应用的web.xml文件中进行如下配置：
<!--spring在应用中的全局参数-->

<context-param>
<param-name>contextConfigLocation</param-name>

<!--支持classpath协议，便于多文件的配置-->
<param-value>classpath*:spring/**.spring.xml</param-value>
</context-param>
<!-- 启动spring容器的监听器-->
<listener>
<listenerclass>
                org.springframework.web.context.ContextLoaderListener
        </listener-class>
</listener>
初始化spring/**.spring.xml文件中配置的bean对象、初始化国际化相关的对象(MessageSource)等许多初始化工作就是在ContextLoaderListener中完成，当这些步骤执行完后就是执行刷新上下文事件，详细解析如下：

if (this.context == null) {

this.context = createWebApplicationContext(servletContext);

}

if (this.context instanceof ConfigurableWebApplicationContext) {

configureAndRefreshWebApplicationContext((ConfigurableWebApplicationContext)this.context, servletContext);

 

}

对于createWebApplicationContext方法：

protected WebApplicationContext createWebApplicationContext(ServletContext sc) {

Class<?> contextClass = determineContextClass(sc);

if (!ConfigurableWebApplicationContext.class.isAssignableFrom(contextClass)) {

throw new ApplicationContextException("Custom context class [" + contextClass.getName() +

"] is not of type [" + ConfigurableWebApplicationContext.class.getName() + "]");

}

ConfigurableWebApplicationContext wac =

(ConfigurableWebApplicationContext) BeanUtils.instantiateClass(contextClass);

return wac;

 

}

 

所以会走configureAndRefreshWebApplicationContext方法，该方法的结尾就有如下代码：

customizeContext(sc, wac);

 

wac.refresh();

ConfigurableWebApplicationContext 是一个接口，其抽象实现类是：AbstractApplicationContext类

其中的refresh方法：

synchronized (this.startupShutdownMonitor) {

// Prepare this context for refreshing.

prepareRefresh();

 

// Tell the subclass to refresh the internal bean factory.

ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory();

 

// Prepare the bean factory for use in this context.

prepareBeanFactory(beanFactory);

 

try {

// Allows post-processing of the bean factory in context subclasses.

postProcessBeanFactory(beanFactory);

 

// Invoke factory processors registered as beans in the context.

invokeBeanFactoryPostProcessors(beanFactory);

 

// Register bean processors that intercept bean creation.

registerBeanPostProcessors(beanFactory);

 

// Initialize message source for this context.

initMessageSource();

 

// Initialize event multicaster for this context.

initApplicationEventMulticaster();

 

// Initialize other special beans in specific context subclasses.

onRefresh();

 

// Check for listener beans and register them.

registerListeners();

 

// Instantiate all remaining (non-lazy-init) singletons.

finishBeanFactoryInitialization(beanFactory);

 

// Last step: publish corresponding event.

finishRefresh();

}

 

catch (BeansException ex) {

// Destroy already created singletons to avoid dangling resources.

destroyBeans();

 

// Reset 'active' flag.

cancelRefresh(ex);

 

// Propagate exception to caller.

throw ex;

}

}

/**
* Finish the refresh of this context, invoking the LifecycleProcessor's
* onRefresh() method and publishing the
* {@link org.springframework.context.event.ContextRefreshedEvent}.
*/

protected void finishRefresh() {

// Initialize lifecycle processor for this context.

initLifecycleProcessor();

 

// Propagate refresh to lifecycle processor first.

getLifecycleProcessor().onRefresh();

 

// Publish the final event.

publishEvent(new ContextRefreshedEvent(this));

}

 

发现publishEvent(new ContextRefreshedEvent(this));这行代码就是发布上下文的事件，我们可自己定义一个监听器让其实现ApplicationListener接口，覆盖onApplicationEvent方法，在onApplicationEvent方法中编写想关的业务逻辑：代码如下：

public class custContextListener implements ApplicationListener {
public void onApplicationEvent(ApplicationEvent event) {
if(event instanceof ContextRefreshedEvent) {

}
}
}