bean生命周期2

后处理bean BeanPostProcessor

1编写实现类

package com.itheima.e_lifecycle;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;

import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.BeanPostProcessor;

public class MyBeanPostProcessor implements BeanPostProcessor {

	@Override
	public Object postProcessBeforeInitialization(Object bean, String beanName)
			throws BeansException {
		System.out.println("前方法");
		return bean;
	}

	@Override
	public Object postProcessAfterInitialization(final Object bean, String beanName)
			throws BeansException {
		System.out.println("后方法");
		//目标对象
		//生成jdk 代理 目的在目标方法前后执行（例如开启事务，提交事务）
		
		
		return Proxy.newProxyInstance(MyBeanPostProcessor.class.getClassLoader(), 
				bean.getClass().getInterfaces(), 
				new InvocationHandler() {
					
					@Override
					public Object invoke(Object proxy, Method method, Object[] args)
							throws Throwable {
						// TODO Auto-generated method stub
						
						System.out.println("----开启事务");
						//执行目标方法
						Object obj =  method.invoke(bean, args) ;
						System.out.println("-----提交事务");
						return obj;
					}
				}) ;
	}



}

2配置

	<!-- 将后处理bean的实现类注册给spring -->
	<bean class="com.itheima.e_lifecycle.MyBeanPostProcessor"></bean>