Spring中Bean的生命周期方法

Bean的生命周期方法

src\dayday\Car.java

package dayday;

import com.sun.org.apache.xpath.internal.SourceTree;

import javax.sound.midi.Soundbank;

/** * Created by I am master on 2016/11/28. */public class Car {    private String name;    public void setName(String name){        this.name=name;        System.out.println("setName...");    }    public String getName(){        return name;    }    public String toString(){        return "["+"carname="+name+"]";    }    public Car(){        System.out.println("Car‘s constructor...");    }    public void init(){        System.out.println("init...");    }    public void destroy(){        System.out.println("destroy...");    }}

src\dayday\Main.java

package dayday;

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

import java.net.SocketTimeoutException;import java.sql.SQLException;

/** * Created by I am master on 2016/11/28. */public class Main {    public static void main(String[] args) throws SQLException, ClassNotFoundException {       ClassPathXmlApplicationContext ctx=new ClassPathXmlApplicationContext("beans.xml");        Car car=ctx.getBean("car",Car.class);        System.out.println(car);        //用close（）方法是就会调用bean对应的destroy()方法         ctx.close();    }}

src\beans.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" xmlns:p="http://www.springframework.org/schema/p"       xmlns:context="http://www.springframework.org/schema/context"       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">       <bean id="car" class="dayday.Car" init-method="init" destroy-method="destroy">           <property name="name" value="Audi"/>       </bean></beans>

运行结果

Car‘s constructor...
setName...
init...

[carname=Audi]
destroy...

bean的生命周期进行管理的过程分为五步

1）通过构造方法或工厂方法创建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）使用bean

5）当spring容器关闭时，调用bean的销毁方法

bean后置处理器

在调用初始化工作前后对bean进行额外的操作

需要实现BeanPostProcessor接口

postProcessBeforeInitialization(Object bean, String beanName)在调用init()方法之前调用

postProcessAfterInitialization(Object bean, String beanName)在调用init()方法之后调用

src\dayday\MyBeanPostProcessor.java

package dayday;

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

/** * Created by I am master on 2016/11/29. */public class MyBeanPostProcessor implements BeanPostProcessor {    @Override    public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {        System.out.println("postProcessBeforeInitialization  "+bean+"  "+beanName);        return bean;    }

@Override    public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {        System.out.println("postProcessAfterInitialization  "+bean+"  "+beanName);        return bean;    }}

Main/Car.java代码不发生变化

src\bean.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" xmlns:p="http://www.springframework.org/schema/p"xmlns:context="http://www.springframework.org/schema/context"xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd"><bean id="car" class="dayday.Car" init-method="init" destroy-method="destroy">    <property name="name" value="Audi"/></bean>    <!--配置bean的后置处理器-->    <bean class="dayday.MyBeanPostProcessor"></bean></beans>

运行结果：Car‘s constructor...
setName...
postProcessBeforeInitialization  [carname=Audi]  car
init...
postProcessAfterInitialization  [carname=Audi]  car[carname=Audi]
destroy...

//调用close()方式是就会调用bean中的destroy()方法