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