(七)SpringIOC容器中bean生命周期

SpringIOC容器可以管理Bean的生命周期Spring允许在Bean生命周期的特定点执行定制任务。
SpringIOC容器对Bean的生命周期进行管理的过程：
1.通过构造器或工厂方法创建Bean实例
2.为Bean的属性设置值和对其他Bean的引用
3.调用Bean的初始化方法
4.Bean可以使用了
5.当容器关闭时，调用Bean 的销毁方法
第一步：配置xml文件
<这里写代码片?xml version=”1.0” encoding=”UTF-8”?>

package com.atguigu.spring.beans.cycle;import org.springframework.beans.BeansException;import org.springframework.beans.factory.config.BeanPostProcessor;public class MyBeanPostProcessor implements BeanPostProcessor {    @Override    public Object postProcessBeforeInitialization(Object  bean, String beanName)            throws BeansException {        //postProcess是处理所有bean的所以处理时要进行过滤        System.out.println("postProcessBeforeInitialization:"+bean+","+beanName);        //Car car=new Car();        //if("car".equals(beanName)){           //car.setBrand("ford");         //}        return bean;    }    //初始化之后执行该方法        @Override        public Object postProcessAfterInitialization(Object bean, String beanName)                throws BeansException {            System.out.println("postProcessAfterInitialization:"+bean+","+beanName);            Car car=new Car();            car.setBrand("ford");            return car;        }}

第三步：新建bean类

public class Car {    public Car(){        System.out.println("Car's Constructor....");    }    private String brand;    public void setBrand(String brand){        System.out.println("setBrand...");        this.brand=brand;    }    public void init2(){        System.out.println("init.....");    }    public void destroy(){        System.out.println("destroy.....");    }    @Override    public String toString() {        return "Car [brand=" + brand + "]";    }}

第四步：执行main方法

package com.atguigu.spring.beans.cycle;import org.springframework.context.support.ClassPathXmlApplicationContext;public class Main {    public static void main(String[] args) {        ClassPathXmlApplicationContext ctx=new ClassPathXmlApplicationContext("beans-cycle.xml");        Car car=(Car) ctx.getBean("car");        System.out.println("tostring:"+car);        //关闭IOC容器        ctx.close();            }}