BeanPostProcessor 接口也被称为后置处理器，通过该接口可以自定义调用初始化前后执行的操作方法。
postProcessBeforeInitialization 方法是在 Bean 实例化和依赖注入后，自定义初始化方法前执行的；而 postProcessAfterInitialization 方法是在自定义初始化方法后执行的。
1. 创建实体类
package com.clzhang.spring.demo; public class HelloWorld { private String message; public void setMessage(String message) { this.message = message; } public void getMessage() { System.out.println("message : " + message); } public void init() { System.out.println("调用XML配置文件中指定的init方法......"); } public void destroy() throws Exception { System.out.println("调用XML配置文件中指定的destroy方法......"); } }
2. 创建BeanPostProcessor接口实现类
package com.clzhang.spring.demo; import org.springframework.beans.BeansException; import org.springframework.beans.factory.config.BeanPostProcessor; public class InitHelloWorld implements BeanPostProcessor { @Override public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException { System.out.println("InitHelloWorld Before : " + beanName); return bean; } @Override public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException { System.out.println("InitHelloWorld After : " + beanName); return bean; } }
3. 创建主程序
package com.clzhang.spring.demo; import org.springframework.context.support.AbstractApplicationContext; import org.springframework.context.support.ClassPathXmlApplicationContext; public class MainApp { public static void main(String[] args) { AbstractApplicationContext context = new ClassPathXmlApplicationContext("Beans.xml"); HelloWorld objA = (HelloWorld) context.getBean("helloWorld"); objA.setMessage("对象A"); objA.getMessage(); context.registerShutdownHook(); } }
4. 配置文件
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.springframework.org/schema/beans" xmlns:context="http://www.springframework.org/schema/context" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd"> <bean id="helloWorld" class="com.clzhang.spring.demo.HelloWorld" init-method="init" destroy-method="destroy"> <property name="message" value="Hello World!" /> </bean> <bean class="com.clzhang.spring.demo.InitHelloWorld" /> </beans>
5. 运行
InitHelloWorld Before : helloWorld
调用XML配置文件中指定的init方法......
InitHelloWorld After : helloWorld
message : 对象A
调用XML配置文件中指定的destroy方法......
本文参考：
http://c.biancheng.net/spring/bean-post-processor.html
Spring深入浅出（三），BeanPostProcessor（Spring后置处理器）
原文：https://www.cnblogs.com/nayitian/p/14998734.html