之前一篇写了ApplicationListener在spring中的实现

这次写的demo试一下这个接口

先上代码

@Servicepublic class BeanPostprocessorTest implements BeanPostProcessor, ApplicationListener{    public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {        System.out.println("++++++++++++++++++++++postProcessAfterInitialization ++++++++++++++++++++++++++");        System.out.println(beanName);        return bean;    }    public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {        // TODO Auto-generated method stub        return bean;    }        public void onApplicationEvent(ApplicationEvent event) {        System.out.println("++++++++++++++++++++++ApplicationEvent ++++++++++++++++++++++++++");        System.out.println(event.getClass().getName());            }}

这个类特别简单，但是同时实现了两个接口

BeanPostProcessor, ApplicationListener

可以只看ApplicationListener的onApplicationEvent

里面可以取到event的实现类

启动spring容器之后可以看到控制台输出了

++++++++++++++++++++++ApplicationEvent ++++++++++++++++++++++++++

org.springframework.context.event.ContextRefreshedEvent

++++++++++++++++++++++ApplicationEvent ++++++++++++++++++++++++++

org.springframework.context.event.ContextStartedEvent

 

也就是说在context refresh 和 start的时候都会执行这个方法

再看一个更实际的例子

dubbo的ServiceBean类同样实现了ApplicationListener这个接口

具体代码如下

public void onApplicationEvent(ApplicationEvent event) {        if (ContextRefreshedEvent.class.getName().equals(event.getClass().getName())) {            if (isDelay() && ! isExported() && ! isUnexported()) {                if (logger.isInfoEnabled()) {                    logger.info("The service ready on spring started. service: " + getInterface());                }                export();            }        }    }

大概意思是当ContextRefreshed时，执行export方法

下一篇说一下BeanPostProcessor这个接口