IOC容器-bean的生命周期

初始化和销毁方法需要配置

xml配置文件：

<?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:util="http://www.springframework.org/schema/util"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
                            http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util.xsd">

    <bean id="book" class="com.spring5.Book" init-method="initMethod" destroy-method="destroyMethod">
        <property name="bname" value="西游记"></property>
    </bean>
</beans>

Book类：

package com.spring5;

public class Book {
    private String bname;

    public Book() {
        System.out.println("第一步，执行无参构造方法创建bean实例");
    }
    public void setBname(String bname) {
        this.bname = bname;
        System.out.println("第二步：调用set方法设置属性值");
    }

    public void initMethod(){
        System.out.println("第三步：执行初始化方法");
    }
    public void  destroyMethod(){
        System.out.println("第五步：执行销毁方法");
    }
}

测试类：

package com.spring5.testdemo;

import com.spring5.Book;
import org.junit.Test;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class testspring5 {

    @Test
    public void test(){
        ClassPathXmlApplicationContext context =
                new ClassPathXmlApplicationContext("com/bean2.xml");
//        第四步：获取创建bean实例对象
        Book book = context.getBean("book", Book.class);
        System.out.println(book);

        context.close();
    }
}

控制台显示生命周期完整过程：

加上bean后置处理器，还有多出两步

1）创建类，实现BeanPostProcessor接口

package com.spring5;

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


public class MyBookbean implements BeanPostProcessor {

    @Override
    public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
        System.out.println("在初始化之前");
        return bean;
    }

    @Override
    public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
        System.out.println("在初始化之后");
        return bean;
    }
}

2）修改spring配置文件

<?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="book" class="com.spring5.Book" init-method="initMethod" destroy-method="destroyMethod">
        <property name="bname" value="西游记"></property>
    </bean>

    <bean id="mybookbean" class="com.spring5.MyBookbean"></bean>
</beans>

控制台显示生命周期过程：