Spring（八）—— bean的生命周期

一、bean的生命周期图

 

 

 

二、bean的生命周期图解释

instantiate bean：对象实例化（new一个对象）

populate properties：封装属性（把xml中数据封装到对象中去）

如果bean实现BeanNameAware，执行setBeanName

如果bean实现BeanFactoryAware，执行setBeanFactory，获取Spring容器

如果存在类实现BeanPostProcessor（后处理bean），执行postProcessAfterInitialization

如果bean实现InitializingBean，执行afterPropertiesSet

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

如果存在类实现BeanPostProcessor（处理Bean），执行postProcessAfterInitialization执行业务处理

如果bean实现DisposableBean执行destory。

调用<bean destory-method="customerDestory">指定销毁方法customerDestory

 

三、案例

1. User.java

package com.gyf.model;


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;

public class User implements BeanNameAware,BeanFactoryAware,InitializingBean,DisposableBean{

    private String username;
    private String password;

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        System.out.println("2. 赋值属性username：" + username);
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        System.out.println("2. 赋值属性password：" + password);
        this.password = password;
    }

    public User() {
        System.out.println("1. 实例化。。。");
    }

    @Override
    public String toString() {
        return "User{" +
                "username='" + username + '\'' +
                ", password='" + password + '\'' +
                '}';
    }

    @Override
    public void setBeanName(String s) {
        System.out.println("3. 设置bean的名字(为配置文件中bean的id)" + s);
    }

    @Override
    public void setBeanFactory(BeanFactory beanFactory) throws BeansException {
        //bean工厂就是容器，意思是把我们的user对象放进工厂（容器）中去
        System.out.println("4. Bean工厂" + beanFactory);
    }

    @Override
    public void afterPropertiesSet() throws Exception {
        System.out.println("6. 属性赋值完成。");
    }

    public void myInit(){
        System.out.println("7. 自定义的初始化方法。");
    }

    @Override
    public void destroy() throws Exception {
        //资源释放
        System.out.println("9. Bean对象被销毁（不用的时候从容器中移除）。");
    }

    public void myDestory(){
        //资源释放
        System.out.println("10. 自定义的销毁方法。");
    }
}

 

2. MyBeanPostProcessor.java

package com.gyf.model;

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 {
        System.out.println("5. 预处理" + bean + beanName);
        return bean;
    }

    @Override
    public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
        System.out.println("8. 后处理" + bean + beanName);
        return bean;
    }
}

 

3. beans5.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="user" class="com.gyf.model.User" init-method="myInit" destroy-method="myDestory">
        <property name="username" value="admin"></property>
        <property name="password" value="123456"></property>
    </bean>

    <!--配置bean处理器-->
    <bean id="beanProcess" class="com.gyf.model.MyBeanPostProcessor"></bean>
</beans>

 

4. Lesson05.java

package com.gyf.test;

import com.gyf.model.User;

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

import java.lang.reflect.InvocationTargetException;

public class Lesson05 {

    @Test
    public void test1() throws NoSuchMethodException, InvocationTargetException, IllegalAccessException {
        ApplicationContext context = new ClassPathXmlApplicationContext("beans5.xml");
        User user = (User) context.getBean("user");
        System.out.println(user);

        //关闭容器
        context.getClass().getMethod("close").invoke(context);
    }

}

 

5. 结果输出如下图：