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当我们使用Spring容器管理对象时，需要对对象进行一些后期处理时，比如数据处理、数据预加载，可以使用BeanPostProcessor接口。
简单演示它的用法。
定义扫描包，显示定义BeanPostProcessor的实现类：
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 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"> <!-- scan the component from the base package --> <context:component-scan base-package="com.nicchagil.springapplication.No004BeanPostProcessor" /> <bean id="myBeanPostProcessor" class="com.nicchagil.springapplication.No004BeanPostProcessor.MyBeanPostProcessor" /> </beans>
实现BeanPostProcessor：
package com.nicchagil.springapplication.No004BeanPostProcessor; import org.springframework.beans.BeansException; import org.springframework.beans.factory.config.BeanPostProcessor; public class MyBeanPostProcessor implements BeanPostProcessor { public Object postProcessBeforeInitialization(Object obj, String arg1) throws BeansException { if (obj != null) { System.out.println("postProcessBeforeInitialization : " + obj.getClass().getName()); } if (obj instanceof UserService) { System.out.println("some operation in this point."); } return obj; } public Object postProcessAfterInitialization(Object obj, String arg1) throws BeansException { if (obj != null) { System.out.println("postProcessAfterInitialization : " + obj.getClass().getName()); } if (obj instanceof UserService) { System.out.println("some operation in this point."); } return obj; } }
被操作的bean：
package com.nicchagil.springapplication.No004BeanPostProcessor; import org.springframework.stereotype.Service; @Service public class UserService { public void queryUser() { System.out.println("query user method."); } }
用于测试的入口类：
package com.nicchagil.springapplication.No004BeanPostProcessor; import org.springframework.context.ApplicationContext; import org.springframework.context.support.ClassPathXmlApplicationContext; public class HowToUse { public static void main(String[] args) { ApplicationContext context = new ClassPathXmlApplicationContext("spring.xml"); UserService us = context.getBean("userService", UserService.class); us.queryUser(); } }
日志：
七月 11, 2016 10:31:13 下午 org.springframework.context.support.ClassPathXmlApplicationContext prepareRefresh 信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@427a39ea: startup date [Mon Jul 11 22:31:13 CST 2016]; root of context hierarchy 七月 11, 2016 10:31:13 下午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions 信息: Loading XML bean definitions from class path resource [spring.xml] 七月 11, 2016 10:31:13 下午 org.springframework.beans.factory.support.DefaultListableBeanFactory preInstantiateSingletons 信息: Pre-instantiating singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@6371be16: defining beans [userService,org.springframework.context.annotation.internalConfigurationAnnotationProcessor,org.springframework.context.annotation.internalAutowiredAnnotationProcessor,org.springframework.context.annotation.internalRequiredAnnotationProcessor,org.springframework.context.annotation.internalCommonAnnotationProcessor,myBeanPostProcessor,org.springframework.context.annotation.ConfigurationClassPostProcessor.importAwareProcessor]; root of factory hierarchy postProcessBeforeInitialization : com.nicchagil.springapplication.No004BeanPostProcessor.UserService some operation in this point. postProcessAfterInitialization : com.nicchagil.springapplication.No004BeanPostProcessor.UserService some operation in this point. query user method.
【Spring】对象后期处理，BeanPostProcessor
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原文地址：http://www.cnblogs.com/nick-huang/p/5661898.html
