[Spring实战系列]（10）初探Bean生命周期

• Spring 对Bean 进行实例化。
• Spring 将值和Bean 的引用注入进Bean 对应的属性中。
• 如果Bean 实现了BeanNameAware接口，Spring 将Bean的ID传递给setBeanName() 接口方法。
• 如果Bean 实现了BeanFactoryAware接口，Spring 将调用setBeanFactory()接口方法，将BeanFactory 容器实例传入。
• 如果Bean 实现了ApplicationContextAware 接口，Spring 将调用setApplicationContext()接口方法，将应用上下文的引用传入。
• 如果Bean 实现了BeanPostProcessor 接口，Spring 将调用它们的postProcessBeforeInitialization() 接口方法。
• 如果Bean 实现了InitializingBean 接口，Spring 将调用它们的afterPropertiesSet() 接口方法。类似地，如果Bean 使用init-method 声明了初始化方法，该方法也会被调用。
• 如果Bean 实现了BeanPostProcessor 接口，Spring 将调用它们的postPoressAfterInitialization() 接口方法。
• 此时此刻，Bean 已经准备就绪，可以被应用程序使用了，它们将一直驻留在应用上下文中，直到该应用上下文被销毁。
• 如果Bean 实现了DisposableBean 接口，Spring 将调用它的destroy()接口方法。同样，如果Bean 使用destroy-method 声明了销毁方法，该方法也会被调用。

package com.sjf.bean;
 
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.BeanFactoryAware;
import org.springframework.beans.factory.BeanNameAware;
import org.springframework.beans.factory.DisposableBean;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
 
/**
 * Student实体类
 * @author sjf0115
 *
 */
public class Student implements BeanNameAware,BeanFactoryAware,InitializingBean,ApplicationContextAware, DisposableBean{
	
	private String name;
	private int age;
	private String school;
	
	// 构造器
	public Student(){
		System.out.println("constructor Student...");
	}
	
	public void setName(String name) {
		this.name = name;
		System.out.println("setName...");
	}
 
	public void setAge(int age) {
		this.age = age;
		System.out.println("setAge...");
	}
 
	public void setSchool(String school) {
		this.school = school;
		System.out.println("setSchool...");
	}
 
	public void myInit(){
		System.out.println("init-method...");
	}
	
	public void myDestroy(){
		System.out.println("destroy-method...");
	}
	
	// 来自于BeanNameAware接口
	public void setBeanName(String arg0) {
		System.out.println("setBeanName...[" + arg0 + "]");
	}
	
	// 来自于BeanFactoryAware接口
	public void setBeanFactory(BeanFactory arg0) throws BeansException {
		System.out.println("setBeanFactory...");
	}
	
	// 来自于InitializingBean
	public void afterPropertiesSet() throws Exception {
		System.out.println("afterPropertiesSet...");
	}
	
	// 来自于DisposableBean
	public void destroy() throws Exception {
		System.out.println("destroy...");
	}
	// 来自于ApplicationContextAware接口
	public void setApplicationContext(ApplicationContext arg0) throws BeansException {
		System.out.println("setApplicationContext...");
	}
	
	@Override
	public String toString() {
		return "name：" + name + "   age：" + age + "   school：" + school;
	}
}

package com.sjf.bean;
 
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.BeanPostProcessor;
 
/**
 * 自定义BeanPostProcessor
 * @author sjf0115
 *
 */
public class MyBeanPostProcessor implements BeanPostProcessor{
	
	public MyBeanPostProcessor(){
		System.out.println("constructor MyBeanPostProcessor...");
	}
	
	// 来自于BeanPostProcessor接口
	public Object postProcessAfterInitialization(Object arg0, String arg1) throws BeansException {
		System.out.println("postProcessAfterInitialization...[" + arg1 + "]");
		return arg0;
	}
		
	// 来自于BeanPostProcessor接口
	public Object postProcessBeforeInitialization(Object arg0, String arg1) throws BeansException {
		System.out.println("postProcessBeforeInitialization...[" + arg1 + "]");
		return arg0;
	}	
}

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
	
	<bean id = "yoona" class = "com.sjf.bean.Student" scope="singleton" init-method="myInit" destroy-method="myDestroy">
		<property name="name" value="yoona"/>
		<property name="age" value="24"/>
		<property name="school" value="西电"/>
	</bean>
	
	<bean id = "myBeanPostProcessor" class="com.sjf.bean.MyBeanPostProcessor"/>
</beans>

package com.sjf.bean;
 
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
 
 
/**
 * 测试类
 * @author sjf0115
 *
 */
public class Test {
 
	private static ApplicationContext context;
	private static Student stu;
	
	public static void main(String[] args) {
		context = new ClassPathXmlApplicationContext("applicationContext.xml");
		// 2. 从IOC容器中获取Bean实例
		stu = (Student)context.getBean("yoona");
		// 3.调用listAllBook方法
		System.out.println(stu.toString());
		// 4.关闭容器
		((ClassPathXmlApplicationContext) context).registerShutdownHook();
	}
}

constructor MyBeanPostProcessor...
constructor Student...
setName...
setAge...
setSchool...
setBeanName...[yoona]
setBeanFactory...
setApplicationContext...
postProcessBeforeInitialization...[yoona]
afterPropertiesSet...
init-method...
postProcessAfterInitialization...[yoona]
name：yoona   age：24   school：西电
destroy...
destroy-method...