Spring容器中Bean的生命周期

Spring生命周期分为以下步骤：

1.instantiate bean 对象实例化

2.populate properties 封装属性

3.如果Bean实现BeanNameAware执行setBeanName

4.如果Bean实现BeanFactoryAware或者ApplicationContextAware设置工厂setBeanFactory或者上下文对象setApplicationContext

5.如果存在类实现BeanPostProcessor执行postProcessorBeforeInitialization

6.如果Bean实现InitializingBean执行afterPropertiesSet

7.调用<bean init-method="init">指定初始化方法init

8.BeanPostProcessor执行postProcessorAfterInitialization

9.执行业务处理(自己写的方法代码)

10.如果Bean实现DisposableBean执行destroy

11.调用<bean destroy-method="destroy">指定销毁方法

代码示例：

配置文件：applicationContext.xml

<?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="man" class="com.imooc.ioc.demo3.Man" init-method="setup" destroy-method="teardown">
        <property name="name" value="张三"/>
    </bean>

    <bean class="com.imooc.ioc.demo3.MyBeanPostProcessor"/>
</beans>

Bean：Man.java

package com.imooc.ioc.demo3;

import org.springframework.beans.BeansException;
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;


public class Man implements BeanNameAware,ApplicationContextAware,InitializingBean,DisposableBean{
    private String name;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        System.out.println("第二步：设置属性");
        this.name = name;
    }

    public Man(){
        System.out.println("第一步：初始化");
    }
    public void setup(){
        System.out.println("第七步：MAN被初始化了");
    }
    public void teardown(){
        System.out.println("第十一步：MAN被销毁了");
    }

    @Override
    public void setBeanName(String s) {
        System.out.println("第三步：设置Bean的名称"+s);
    }

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        System.out.println("第四步：了解工厂信息");
    }

    @Override
    public void afterPropertiesSet() throws Exception {
        System.out.println("第六步：属性设置后");
    }

    public void run(){
        System.out.println("第九步：执行业务代码");
    }

    @Override
    public void destroy() throws Exception {
        System.out.println("第十步：执行Spring的销毁对象");
    }
}

最上方5.中的所说的存在的另一个类：MyBeanPostProcessor.java

package com.imooc.ioc.demo3;

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

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

public class MyBeanPostProcessor implements BeanPostProcessor {
    @Override
    public Object postProcessBeforeInitialization(Object bean, String s) throws BeansException {
        System.out.println("第五步：初始化前方法");
        return bean;
    }

    @Override
    public Object postProcessAfterInitialization(final Object bean, String beanName) throws BeansException {
        System.out.println("第八步：初始化后方法");
        return bean;

    }
}

测试类：SpringDemo3.java

package com.imooc.ioc.demo3;

import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class SpringDemo3 {

    @Test
    public void demo2(){
        ClassPathXmlApplicationContext applicationContext = new ClassPathXmlApplicationContext("applicationContext.xml");
        Man man = (Man) applicationContext.getBean("man");
        man.run();
        applicationContext.close();
    }

}

执行demo2方法，打印结果：