Spring 的几个接口
1.InitializingBean接口，在初始化Bean时容器会调用前者的afterPropertiesSet()方法
2.DisposableBean接口，在析构Bean时容器会调用destroy()方法，在下面的例子中好像没有体现出来（革命尚未成功，同志仍需努力）
3.BeanFactoryAware接口，当它被BeanFactory创建后，它会拥有一个指向创建它的BeanFactory的引用
4.BeanPostProcessor接口，这个接口两个方法，postProcessBeforeInitialization(Object bean, String beanName)和postProcessAfterInitialization(Object bean, String beanName) 在其他Bean构造前后执行
5.BeanFactoryPostProcessor接口，Spring IoC容器允许BeanFactoryPostProcessor在容器实际实例化任何其它的bean之前读取配置元数据，并有可能修改它
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下面来看一下例子
- package com.test;
- public class User {
- ????private String name;
- ????
- ????public String getName() {
- ????????return name;
- ???? }
- ????public void setName(String name) {
- ???????? System.out.println("User类 setName方法");
- ????????this.name = name;
- ???? }
- ????public void init() throws Exception {
- ???????? System.out.println("User类init 方法");
- ????????
- ???? }
- ????public User(){
- ???????? System.out.println("User类构造方法");
- ???? }
- ????
- }
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- package com.test;
- import org.springframework.beans.BeansException;
- import org.springframework.beans.factory.BeanFactory;
- import org.springframework.beans.factory.BeanFactoryAware;
- import org.springframework.beans.factory.DisposableBean;
- import org.springframework.beans.factory.InitializingBean;
- import org.springframework.beans.factory.config.BeanFactoryPostProcessor;
- import org.springframework.beans.factory.config.BeanPostProcessor;
- import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
- public class JavaBean implements InitializingBean,DisposableBean,BeanFactoryAware,BeanPostProcessor ,BeanFactoryPostProcessor{
- ????private String name;
- ????public JavaBean(){
- ???????? System.out.println("JavaBean类构造方法");
- ???? }
- ????@Override
- ????public void afterPropertiesSet() throws Exception {
- ???????? System.out.println("InitializingBean 接口 afterPropertiesSet方法");
- ????????
- ???? }
- ????@Override
- ????public void destroy() throws Exception {
- ???????? System.out.println("DisposableBean 接口 destroy方法");
- ????????
- ???? }
- ????public void init() throws Exception {
- ???????? System.out.println("JavaBean类init 方法");
- ????????
- ???? }
- ????@Override
- ????public void setBeanFactory(BeanFactory beanFactory) throws BeansException {
- ???????? System.out.println("BeanFactoryAware 接口 setBeanFactory方法");
- ????????
- ???? }
- ????@Override
- ????public Object postProcessAfterInitialization(Object bean, String beanName)
- ????????????throws BeansException {
- ???????? System.out.println(beanName+":BeanPostProcessor 接口 postProcessAfterInitialization方法");
- ????????return bean;
- ???? }
- ????@Override
- ????public Object postProcessBeforeInitialization(Object bean, String beanName)
- ????????????throws BeansException {
- ???????? System.out.println(beanName+":BeanPostProcessor 接口 postProcessBeforeInitialization 方法");
- ????????return bean;
- ???? }
- ????public String getName() {
- ????????return name;
- ???? }
- ????public void setName(String name) {
- ???????? System.out.println("JavaBean类setName 方法");
- ????????this.name = name;
- ???? }
- ????@Override
- ????public void postProcessBeanFactory(
- ???????????? ConfigurableListableBeanFactory beanFactory) throws BeansException {
- ???????? System.out.println("BeanFactoryPostProcessor 接口 postProcessBeanFactory 方法");
- ???? }
- ????
- }
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- package com.test;
- import org.springframework.context.ApplicationContext;
- import org.springframework.context.support.ClassPathXmlApplicationContext;
- public class Test {
- ????/**
- ????? * @param args
- ????? */
- ????public static void main(String[] args) {
- ???????? System.out.println("加载Spring配置文件");
- ????????? ApplicationContext context =??
- ????????????????new ClassPathXmlApplicationContext("spring.xml");
- ????????? System.out.println("加载Spring配置文件结束");
- ????????? JavaBean bean=(JavaBean)context.getBean("javaBean");
- ????????? System.out.println("获取name属性："+bean.getName());
- ????????? System.out.println("程序结束");
- ???? }
- }
Spring配置文件
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- <?xml version="1.0" encoding="UTF-8"?>
- <!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd">
- <beans>
- ????<bean id="javaBean" class="com.test.JavaBean" init-method="init">
- ????????<property name="name" value="zhjb"></property>
- ????</bean>
- ????<bean id="user" class="com.test.User" init-method="init">
- ????????<property name="name" value="zhjb" ></property>
- ????</bean>
- </beans>
运行结果如下：
加载Spring配置文件
JavaBean类构造方法
JavaBean类setName 方法
BeanFactoryAware 接口 setBeanFactory方法
InitializingBean 接口 afterPropertiesSet方法
JavaBean类init 方法
BeanFactoryPostProcessor 接口 postProcessBeanFactory 方法
User类构造方法
User类 setName方法
user:BeanPostProcessor 接口 postProcessBeforeInitialization 方法
User类init 方法
user:BeanPostProcessor 接口 postProcessAfterInitialization方法
加载Spring配置文件结束
获取name属性：zhjb
程序结束
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从结果进行分析，Bean的初始化顺序应该是
1.构造函数
2.初始化属性
3.如果实现了BeanFactoryAware 接口执行setBeanFactory方法
4..如果实现了InitializingBean 接口执行afterPropertiesSet方法
5.如果在配置文件中指定了init-method，那么执行该方法
6..如果实现了BeanFactoryPostProcessor 接口在 “new”其他类之前执行 postProcessBeanFactory 方法（通过这个方法可以改变配置文件里面的属性值的配置）
7.如果实现了BeanFactoryPostProcessor 接口，那么会在其他bean初始化方法之前执行postProcessBeforeInitialization 方法，之后执行postProcessAfterInitialization方法
感觉奇怪的地方就是没有执行destroy方法，目前还不知道原因在什么地方