AnnotationConfigApplicationContext-initApplicationEventMulticaster

initApplicationEventMulticaster

初始化ApplicationEventMulticaster事件，默认使用SimpleApplicationEventMulticaster事件

protected void initApplicationEventMulticaster() {
		//获取BeanFactory
		ConfigurableListableBeanFactory beanFactory = getBeanFactory();
		/**
		 * 判断容器中是否存在bdName为applicationEventMulticaster的bd
		 * 也就是自定义的事件监听多路广播器，必须实现ApplicationEventMulticaster接口
		 */
		if (beanFactory.containsLocalBean(APPLICATION_EVENT_MULTICASTER_BEAN_NAME)) {
			this.applicationEventMulticaster =
					beanFactory.getBean(APPLICATION_EVENT_MULTICASTER_BEAN_NAME, ApplicationEventMulticaster.class);
			if (logger.isDebugEnabled()) {
				logger.debug("Using ApplicationEventMulticaster [" + this.applicationEventMulticaster + "]");
			}
		}
		else {
			/**
			 * 如果没有，则默认采用SimpleApplicationEventMulticaster，并注册为单例
			 */
			this.applicationEventMulticaster = new SimpleApplicationEventMulticaster(beanFactory);
			beanFactory.registerSingleton(APPLICATION_EVENT_MULTICASTER_BEAN_NAME, this.applicationEventMulticaster);
			if (logger.isDebugEnabled()) {
				logger.debug("Unable to locate ApplicationEventMulticaster with name '" +
						APPLICATION_EVENT_MULTICASTER_BEAN_NAME +
						"': using default [" + this.applicationEventMulticaster + "]");
			}
		}
	}