Spring Bean生命周期的各阶段介绍

一.xml方式配置bean

二.Aware接口

  2.1 BeanNameAware

  2.2 BeanFactoryAware

  2.3 ApplicationContextAware

  2.4 Aware各接口的执行顺序

  2.4 Aware接口总结

三.BeanPostProcessor接口

四.InitializingBean接口

五.init-method方法

六.DestructionAwareBeanPostProcessor接口

七.DisposableBean接口

八.destory-method方法

九.生命周期大杂烩

  9.1 实现多接口的Student类

  9.2 BeanPostProcessor前后置处理

  9.3 DestructionAwareBeanPostPrecessor接口

  9.4 配置xml文件

  9.5 测试代码

  9.6 输出结果

十.总结

 

 

 

 

  Spring Bean的生命周期是一个老生常谈的问题了,网上一搜一大把,无非就是画一幅流程图(比如下面这幅图),然后用语言介绍创建bean后执行各Aware接口,然后BeanPostProcessor.....最终Bean创建成功了,就可以使用这个Bean了,然后在容器销毁的时候,又会执行一些操作。

Spring Bean生命周期的各阶段介绍_第1张图片

  其实对于上面的提到的流程图,注意上面的图只是Spring Bean的大概流程(省略了一部分),主要涉及到了5个接口,分别是XxxAware、BeanPostProcessor、InitiailizingBean、Destruction、DisposableBean接口,本文将会对这几个接口,以及init-method、destroy-method做相关的使用介绍,在明白怎么使用后,再把他们串起来,这样的话,对于Spring Bean的生命周期就差不多知道咋回事了,而不用死记硬背。

 

一. xml方式配置Bean

  在说Aware、BeanPostProcessor、InitiailizingBean、Destruction、DisposableBean这些接口前,先简单回顾一下使用xml配置并获取一个Student类的bean过程,后面介绍各个接口的使用方式时时,也是按照这个形式;

1.1 创建Student类

  平淡无奇的Student类:

package cn.ganlixin.entity;

import lombok.Data;
import lombok.extern.slf4j.Slf4j;

@Data
@Slf4j
public class Student {

    private Integer id;
    private String name;
}

  

1.2 创建配置文件

  平淡无奇的applicationContext.xml配置文件,创建一个student bean,利用setter方式设置初始值:




    
        
        
    

  

1.3 测试

  创建一个Main类,用于测试

package cn.ganlixin;

import cn.ganlixin.entity.Student;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.xml.XmlBeanFactory;
import org.springframework.core.io.ClassPathResource;

@Slf4j
public class Test {

    public static void main(String[] args) {
        BeanFactory beanFactory = new XmlBeanFactory(new ClassPathResource("applicationContext.xml"));

        Student student = beanFactory.getBean("student", Student.class);
        log.info("测试程序获取到的student bean:{}", student);
    }
}

  下面是运行程序的输出,可以看到和预期相符,创建一个Student的bean,id和name默认值为99、张三;

INFO  [main] cn.ganlixin.Test - 测试程序获取到的student bean:Student(id=99, name=张三)

   

二.Aware接口

  Aware接口有很多实现类,本文只介绍BeanNameAware、BeanFactoryAware、ApplicationContextAware,关系如下:

  Spring Bean生命周期的各阶段介绍_第2张图片

 

2.1 BeanNameAware

  创建一个Student类,让该类实现BeanNameAware接口,并且重写setBeanName方法

@Data
@Slf4j
public class Student implements BeanNameAware {

    private Integer id;
    private String name;

    /**
     * 实现了BeanNameAware接口后,需重写setBeanName方法,接收的参数就是bean的id
     *
     * @param s bean的id
     */
    @Override
    public void setBeanName(String s) {
        log.info("beanName:{}, student bean:{}", s, this);
        this.id = 100;
        log.info("将beanName:{}的id改为100", s);
    }
}

  配置文件和测试程序都不改变,运行测试程序,输出内容如下:

INFO  [main] cn.ganlixin.entity.Student - beanName:student, student bean:Student(id=99, name=张三)
INFO  [main] cn.ganlixin.entity.Student - 将beanName:student的id改为100
INFO  [main] cn.ganlixin.Test - 测试程序获取到的student bean:Student(id=100, name=张三)

  可以看到,实现BeanNameAware接口后,重写setBeanName的方法中,获取到的student bean,是已经初始化的bean(属性都已经有值了),并且setBeanName方法中可以对当前的bean进行各种操作,包括修改bean的某些属性,最后获取到的bean是已经修改后的bean。

  这里只是简单介绍了一下BeanNameAware接口的用法,使用BeanNameAware接口,可以对当前Bean进行操作

 

2.2 BeanFactoryAware

  创建Student类,实现BeanFactoryAware接口,并且重写setBeanFactory方法

@Data
@Slf4j
public class Student implements BeanFactoryAware {

    private Integer id;
    private String name;

    /**
     * 实现BeanFactoryAware接口后,需重写setBeanFactroy方法
     *
     * @param beanFactory 创建该bean的beanFactory
     */
    @Override
    public void setBeanFactory(BeanFactory beanFactory) throws BeansException {
        // 可以在setBeanFactory方法中获取、修改beanFactory中的所有bean
        
        log.info("student this bean:{}", this);
        Student student = beanFactory.getBean("student", Student.class);
        log.info("通过beanFactory获取student bean:{}", student);

        // 将name设置为李四
        this.name = "李四";
    }
}

  运行输出如下:

INFO  [main] cn.ganlixin.entity.Student - student this bean:Student(id=99, name=张三)
INFO  [main] cn.ganlixin.entity.Student - 通过beanFactory获取student bean:Student(id=99, name=张三)
INFO  [main] cn.ganlixin.Test - 测试程序获取到的student bean:Student(id=99, name=李四)

  通过上面的代码输出结果可以看出,实现BeanFactoryAware接口后,可以在setBeanFactory方法中操作BeanFactory的所有bean,操作的范围要比BeanNameAware要大。

 

2.3 ApplicationContextAware

  ApplicationContext,有多种称呼,比如“应用容器”、“环境”、“上线文”...

  创建Student类,实现ApplicationContextAware接口,并且重写setApplicationContext接口:

@Data
@Slf4j
public class Student implements ApplicationContextAware {

    private Integer id;
    private String name;

    /**
     * 实现ApplicationContextAware接口后,徐重写setApplicationContext方法
     *
     * @param applicationContext 该bean所在的上下文(applicationContext、容器)
     */
    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        log.info("Student this:{}", this);

        final Student student = applicationContext.getBean("student", Student.class);
        final Environment environment = applicationContext.getEnvironment();
        log.info("student bean:{}", student);
        log.info("env -> user.dir:{}", environment.getProperty("user.dir"));
    }
}

  需要修改一下测试程序,测试程序中加载配置时使用的XmlBeanFactory,而XmlBeanFactory不会回调ApplicationContextAware接口的setApplicationContext方法,下面使用ClassPathXmlApplicationContext类来加载配置:

@Slf4j
public class Test {

    public static void main(String[] args) {
        //BeanFactory beanFactory = new XmlBeanFactory(new ClassPathResource("applicationContext.xml"));

        // 使用ApplicationContext来加载配置
        ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
        Student student = context.getBean("student", Student.class);
        log.info("测试程序获取到的student bean:{}", student);
    }
}

  运行测试程序:

INFO  [main] cn.ganlixin.entity.Student - Student this:Student(id=99, name=张三)
INFO  [main] cn.ganlixin.entity.Student - student bean:Student(id=99, name=张三)
INFO  [main] cn.ganlixin.entity.Student - env -> user.dir:/Users/ganlixin/code/java-code-all/spring
INFO  [main] cn.ganlixin.Test - 测试程序获取到的student bean:Student(id=99, name=张三)

  实现ApplicationContextAware接口后,在setApplicationContext方法中,入参是当前的applicationContext,也就是说,可以在该方法中对Spring容器进行设置,操作的范围又要比BeanFactoryAware的setBeanFactory要广得多。

 

2.4 Aware各接口执行的先后顺序

  既然有这几个Aware接口,如果一个类同时实现了这3个接口,那么执行顺序是怎样的呢?下面就来测试一下。

  创建Student类,分别实现BeanNameAware、BeanFactoryAware、ApplicationContextAware接口,并重写其接口的方法:

@Data
@Slf4j
public class Student implements BeanNameAware, BeanFactoryAware, ApplicationContextAware {

    private Integer id;
    private String name;

    /**
     * 实现了BeanNameAware接口后,需重写setBeanName方法,接收的参数就是bean的id
     *
     * @param s bean的id
     */
    @Override
    public void setBeanName(String s) {
        log.info("call BeanNameAware.setBeanName()");
    }

    /**
     * 实现BeanFactoryAware接口后,需重写setBeanFactroy
     *
     * @param beanFactory 创建该bean的bean工厂
     */
    @Override
    public void setBeanFactory(BeanFactory beanFactory) throws BeansException {
        log.info("call BeanFactoryAware.setBeanFactory()");
    }

    /**
     * 实现ApplicationContextAware接口后,徐重写setApplicationContext方法
     *
     * @param applicationContext 该bean所在的上下文(applicationContext、容器)
     */
    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        log.info("call ApplicationContextAware.setApplicationContext()");
    }
}

  仍旧使用ClassPathXmlApplicationContext类来加载配置,运行输出结果如下:

INFO  [main] cn.ganlixin.entity.Student - call BeanNameAware.setBeanName()
INFO  [main] cn.ganlixin.entity.Student - call BeanFactoryAware.setBeanFactory()
INFO  [main] cn.ganlixin.entity.Student - call ApplicationContextAware.setApplicationContext()
INFO  [main] cn.ganlixin.Test - 测试程序获取到的student bean:Student(id=99, name=张三)

  

2.4 Aware接口总结

  上面演示了Spring中几个Aware接口的用法和特点,下面总结一下:

  1.实现BeanNameAware接口后,重写setBeanName方法,可以对单个Bean进行扩展修改;

  2.实现BeanFactoryAware接口后,重写setBeanFactory方法,可以对bean工厂中的所有Bean进行扩展修改;

  3.实现ApplicationContextAware接口后,重写setApplicationContext方法后,可以对整个容器进行扩展修改;

  4.这几个接口的执行顺序分别是BeanNameAware->BeanFactoryAware->ApplicationContextAware;

 

三.BeanPostProcessor接口

  BeanPostProcessor和前面的Aware接口有些区别,通过下面的例子就能看出区别在哪里!

  下面举个例子,创建MyBeanPostProcessor类,实现BeanPostProcessor接口,注意,这里没有在Student类上实现BeanPostProcessor接口。

@Slf4j
public class MyBeanPostProcessor implements BeanPostProcessor {

    /**
     * 实现了BeanPostProcessor接口后,重写postProcessBeforeInitialization,在各种Aware接口执行完毕后执行该方法
     *
     * @param bean     本次处理的bean
     * @param beanName 本次处理的beanName(bean id)
     * @return 返回的是在本方法中处理后的bean
     */
    @Override
    public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
        log.info("MyBeanPostProcessor.postProcessBeforeInitialization, beanName:{}, bean:{}", beanName, bean);
        return bean;
    }

    /**
     * 实现了BeanPostProcessor接口后,重写postProcessBeforeInitialization,在initMethod方法执行完毕后执行该方法
     *
     * @param bean     本次处理的bean
     * @param beanName 本次处理的beanName(bean id)
     * @return 返回的是在本方法中处理后的bean
     */
    @Override
    public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
        log.info("MyBeanPostProcessor.postProcessAfterInitialization, beanName:{}, bean:{}", beanName, bean);
        return bean;
    }
}

  创建两个类,分别是Student和User类,其中Use类没有实现Aware接口,Student类实现了前面提到的3个Aware接口

@Data
public class User {
    private Integer id;
    private String name;
}

  

@Data
@Slf4j
public class Student implements BeanNameAware, BeanFactoryAware, ApplicationContextAware {

    private Integer id;
    private String name;

    /**
     * 实现了BeanNameAware接口后,需重写setBeanName方法,接收的参数就是bean的id
     *
     * @param s bean的id
     */
    @Override
    public void setBeanName(String s) {
        log.info("call BeanNameAware.setBeanName()");
    }

    /**
     * 实现BeanFactoryAware接口后,需重写setBeanFactroy
     *
     * @param beanFactory 创建该bean的bean工厂
     */
    @Override
    public void setBeanFactory(BeanFactory beanFactory) throws BeansException {
        log.info("call BeanFactoryAware.setBeanFactory()");
    }

    /**
     * 实现ApplicationContextAware接口后,徐重写setApplicationContext方法
     *
     * @param applicationContext 该bean所在的上下文(applicationContext、容器)
     */
    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        log.info("call ApplicationContextAware.setApplicationContext()");
    }
}

  

  xml配置文件:




    
        
        
    

    
        
        
    

    
    

  

  测试:

INFO  [main] cn.ganlixin.entity.Student - call BeanNameAware.setBeanName()
INFO  [main] cn.ganlixin.entity.Student - call BeanFactoryAware.setBeanFactory()
INFO  [main] cn.ganlixin.entity.Student - call ApplicationContextAware.setApplicationContext()
INFO  [main] cn.ganlixin.processor.MyBeanPostProcessor - MyBeanPostProcessor.postProcessBeforeInitialization, beanName:student1, bean:Student(id=99, name=张三)
INFO  [main] cn.ganlixin.processor.MyBeanPostProcessor - MyBeanPostProcessor.postProcessAfterInitialization, beanName:student1, bean:Student(id=99, name=张三)
INFO  [main] cn.ganlixin.processor.MyBeanPostProcessor - MyBeanPostProcessor.postProcessBeforeInitialization, beanName:user, bean:User(id=88, name=王五)
INFO  [main] cn.ganlixin.processor.MyBeanPostProcessor - MyBeanPostProcessor.postProcessAfterInitialization, beanName:user, bean:User(id=88, name=王五)
INFO  [main] cn.ganlixin.Test - 测试程序获取到的student bean:Student(id=99, name=张三)

  从上面的运行结果可以得出以下结论:

  1.因为只有Student实现了Aware接口,所以创建student bean的时候会调用对应的Aware接口方法,而User类没有实现Aware接口,所以并没有调用Aware接口方法;

  2.Student和User类都没有继承BeanPostProcessor接口,但是在创建student和user bean的时候,都掉用了MyBeanPostProcessor类中的前置和后置处理(继承自BeanPostProcessor接口);

  3.BeanPostProcessor接口的前置和后置处理,是在Aware接口之后调用;

  4.很重要的一点,需要将BeanPostProcessor接口实现类声明为bean,使用配置或者使用@Component注解,不然BeanPostProcessor不起作用。

 

四.InitializingBean接口

  创建Student类,实现InitializingBean接口,然后重写afterPropertiesSet方法:

@Data
@Slf4j
public class Student implements InitializingBean {

    private Integer id;
    private String name;

    @Override
    public void afterPropertiesSet() throws Exception {
        // 同样可以在这里修改bean的属性值
        log.info("InitialingBean.afterPropertiesSet, this:{}", this);
    }
}

  修改xml配置文件,创建student bean,测试:

INFO  [main] cn.ganlixin.entity.Student - InitialingBean.afterPropertiesSet, this:Student(id=99, name=张三)
INFO  [main] cn.ganlixin.Test - 测试程序获取到的student bean:Student(id=99, name=张三)

  

五.init-method

  创建Student类,增加一个额外的方法display()

@Data
@Slf4j
public class Student {

    private Integer id;
    private String name;

    public void display() {
        log.info("Student.display call, this:{}", this);
    }
}

  修改配置文件,在标签中增加init-method属性,值为display,也就是Student的display方法名:




    
        
        
    

  运行测试:

INFO  [main] cn.ganlixin.entity.Student - Student.display call, this:Student(id=99, name=张三)
INFO  [main] cn.ganlixin.Test - 测试程序获取到的student bean:Student(id=99, name=张三)

  上面,输出了display中的内容,这是在设置bean的时候调用的。

 

六.DestructionAwareBeanPostProcessor接口

  DestructionAwareBeanPostProcessor接口,从名称上可以看出来是DestructionAware + BeanPostProcessor的组合,其实也的确是这样,但是需要注意的就是,spring并没有提供DestructionAware接口!!

  下面是DestructionAwareBeanPostProcessor接口的定义:

public interface DestructionAwareBeanPostProcessor extends BeanPostProcessor {

    /**
     * Destruction执行的操作
     *
     * @param bean     处理的bean
     * @param beanName bean的名称
     * @throws BeansException
     */
    void postProcessBeforeDestruction(Object bean, String beanName) throws BeansException;

    /**
     * 是否需要执行postProcessBeforeDestruction方法
     *
     * @param bean 执行Destruction的bean
     * @return 是否需要执行postProcessBeforeDestruction方法
     */
    default boolean requiresDestruction(Object bean) {
        return true;
    }
}

  DestructionAwareBeanPostProceesor继承自BeanPostProcessor接口,所以也可以重写前值和后置处理。

  下面介绍使用示例,创建MyDestructionAwareBeanPostProceesor,继承DestructionAwareBeanPostProceesor接口:

@Slf4j
public class MyDestructionAwareBeanPostProcessor implements DestructionAwareBeanPostProcessor {

    @Override
    public void postProcessBeforeDestruction(Object bean, String beanName) throws BeansException {
        log.info("DestructionAwareBeanPostProcessor.postProcessBeforeDestruction, \n\tbeanName:{}, bean:{}", beanName, bean);
    }
    
    @Override
    public boolean requiresDestruction(Object bean) {
        return true; // 返回true,一律执行postProcessBeforeDestruction方法
        // 如果返回false,则不执行postProcessBeforeDestruction方法
    }
}

  修改配置文件:




    
        
        
    


    
        
        
    

    
    

  测试程序:

@Slf4j
public class Test {

    public static void main(String[] args) {
        // 使用ApplicationContext来加载配置
        ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
        Student student = context.getBean("student", Student.class);
        User user = context.getBean("user", User.class);

        log.info("测试程序获取到的student bean:{}", student);

        // 获取bean工厂,然后调用destroyBean销毁bean
        AutowireCapableBeanFactory factory = context.getAutowireCapableBeanFactory();
        factory.destroyBean(student);
    }
}

  运行测试程序,输出如下:

INFO  [main] cn.ganlixin.Test - 测试程序获取到的student bean:Student(id=99, name=张三)
INFO  [main] cn.ganlixin.processor.MyDestructionAwareBeanPostProcessor - DestructionAwareBeanPostProcessor.postProcessBeforeDestruction, 
	beanName:cn.ganlixin.entity.Student, bean:Student(id=99, name=张三)

  可以看到,在手动调用destroyBean方法来销毁student bean的时候,调用了MyDestructionAwareBeanPostProcessor中定义的方法。

  需要注意的是,虽然这里使用destroyBean来销毁了student bean,如果又通过getBean来获取student bean,则会重新创建student bean。

 

七.DisposableBean接口 

  前面介绍了DestructionAwareBeanPostProcessor接口,可以对所有的bean设置销毁(destruction)后的处理操作。

  而这里介绍的DisposableBean接口,就是对单独的Bean进行destrction后的处理,也就是说不是应用到所有的bean上。

  简单介绍一下用法,创建Student类和User类,User类正常(不实现任何接口),Student类实现DisposableBean接口,然后重写destroy方法:

@Data
@Slf4j
public class Student implements DisposableBean {

    private Integer id;
    private String name;

    @Override
    public void destroy() throws Exception {
        log.info("DisposableBean.destroy, this:{}", this);
    }
}

@Data
public class User {
    private Integer id;
    private String name;
}

  创建配置文件:




    
        
        
    

    
        
        
    

  测试程序:

@Slf4j
public class Test {

    public static void main(String[] args) {
        // 使用ApplicationContext来加载配置
        ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
        Student student = context.getBean("student", Student.class);
        User user = context.getBean("user", User.class);

        log.info("测试程序获取到的student bean:{}", student);
        log.info("测试程序获取到的user bean:{}",user);

        // 获取bean工厂,然后调用destroyBean销毁bean
        AutowireCapableBeanFactory factory = context.getAutowireCapableBeanFactory();
        factory.destroyBean(student);
        factory.destroyBean(user);
    }
}

  运行输出:

INFO  [main] cn.ganlixin.Test - 测试程序获取到的student bean:Student(id=99, name=张三)
INFO  [main] cn.ganlixin.Test - 测试程序获取到的user bean:User(id=88, name=王五)
INFO  [main] cn.ganlixin.entity.Student - DisposableBean.destroy, this:Student(id=99, name=张三)

  可以看到,虽然测试代码中destroy了student和user两个bean,但是只有student bean在销毁时触发了DisposableBean的destory方法。

 

八.destroy-method方法

  和init-method相对应的就是destory-method方法了,创建Student类,增加clean方法(自定义):

@Data
@Slf4j
public class Student {

    private Integer id;
    private String name;

    public void clean() {
        log.info("Student.clean, this:{}", this);
    }
}

  修改配置文件,标签中使用destroy-method属性,值为clean方法


    
    

  测试程序:

@Slf4j
public class Test {

    public static void main(String[] args) {
        // 使用ApplicationContext来加载配置
        ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
        Student student = context.getBean("student", Student.class);

        log.info("测试程序获取到的student bean:{}", student);

        // 删除bean
        BeanDefinitionRegistry registry = (BeanDefinitionRegistry) context.getAutowireCapableBeanFactory();
        registry.removeBeanDefinition("student");
    }
}

  输出:

INFO  [main] cn.ganlixin.Test - 测试程序获取到的student bean:Student(id=99, name=张三)
INFO  [main] cn.ganlixin.entity.Student - Student.clean, this:Student(id=99, name=张三)

  

九.声明周期大杂烩

  上面对每一种接口都做了介绍,这里就将所有接口都做一下整合,尝试在一个测试程序中测试所有接口,这个过程中就会对Bean的生命周期有清晰的认识:

9.1 实现多接口的Student类

  创建Student类,实现Aware、InitializingBean、DisposableBean接口,并且增加display、clean方法,作为init-method和destory-method。

package cn.ganlixin.entity;

import lombok.Data;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.*;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;

@Data
@Slf4j
public class Student implements BeanNameAware, BeanFactoryAware, ApplicationContextAware, InitializingBean, DisposableBean {

    private Integer id;
    private String name;

    @Override
    public void setBeanName(String s) {
        log.info("BeanNameAware.setBeanName, this:{}", this);
    }

    @Override
    public void setBeanFactory(BeanFactory beanFactory) throws BeansException {
        log.info("BeanFactoryAware.setBeanFactory, this:{}", this);
    }

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        log.info("ApplicationContextAware.setApplicationContext, this:{}", this);
    }

    @Override
    public void afterPropertiesSet() throws Exception {
        log.info("InitialingBean.afterPropertiesSet, this:{}", this);
    }

    @Override
    public void destroy() throws Exception {
        log.info("DisposableBean.destory, this:{}", this);
    }

    public void display() {
        log.info("init-method, Student.display, this:{}", this);
    }

    public void clean() {
        log.info("destroy-method, Student.clean, this:{}", this);
    }
}

 

9.2 BeanPostProcessor前后置处理

  创建MyBeanPostProcessor接口实现类,并重写前置和后置处理方法:

package cn.ganlixin.processor;

import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.BeanPostProcessor;

@Slf4j
public class MyBeanPostProcessor implements BeanPostProcessor {

    @Override
    public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
        log.info("MyBeanPostProcessor.postProcessBeforeInitialization, beanName:{}, bean:{}", beanName, bean);
        return bean;
    }

    @Override
    public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
        log.info("MyBeanPostProcessor.postProcessAfterInitialization, beanName:{}, bean:{}", beanName, bean);
        return bean;
    }
}

 

9.3 DestructionAwareBeanPostPrecessor接口

  创建MyDestructionAwareBeanPostProcessor类,并重写其中的方法(不重写BeanPostProcessor的前后置处理方法):

package cn.ganlixin.processor;

import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.DestructionAwareBeanPostProcessor;

@Slf4j
public class MyDestructionAwareBeanPostProcessor implements DestructionAwareBeanPostProcessor {

    @Override
    public void postProcessBeforeDestruction(Object bean, String beanName) throws BeansException {
        log.info("DestructionAwareBeanPostProcessor.postProcessBeforeDestruction, \n\tbeanName:{}, bean:{}", beanName, bean);
    }

    @Override
    public boolean requiresDestruction(Object bean) {
        return true; // 返回true,一律执行postProcessBeforeDestruction方法
        // 如果返回false,则不执行postProcessBeforeDestruction方法
    }
}

  

9.4 配置xml文件  




    
    
        
        
    


    
    

    
    

  

9.5 测试代码

package cn.ganlixin;

import cn.ganlixin.entity.Student;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

@Slf4j
public class Test {

    public static void main(String[] args) {
        // 使用ApplicationContext来加载配置
        ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
        Student student = context.getBean("student", Student.class);

        log.info("测试程序获取到的student bean:{}", student);

        // 删除bean
        BeanDefinitionRegistry factory = (BeanDefinitionRegistry) context.getAutowireCapableBeanFactory();
        factory.removeBeanDefinition("student");
    }
}

  

9.6 输出结果

INFO  [main] cn.ganlixin.entity.Student - BeanNameAware.setBeanName, this:Student(id=99, name=张三)
INFO  [main] cn.ganlixin.entity.Student - BeanFactoryAware.setBeanFactory, this:Student(id=99, name=张三)
INFO  [main] cn.ganlixin.entity.Student - ApplicationContextAware.setApplicationContext, this:Student(id=99, name=张三)
INFO  [main] cn.ganlixin.processor.MyBeanPostProcessor - MyBeanPostProcessor.postProcessBeforeInitialization, beanName:student, bean:Student(id=99, name=张三)
INFO  [main] cn.ganlixin.entity.Student - InitialingBean.afterPropertiesSet, this:Student(id=99, name=张三)
INFO  [main] cn.ganlixin.entity.Student - init-method, Student.display, this:Student(id=99, name=张三)
INFO  [main] cn.ganlixin.processor.MyBeanPostProcessor - MyBeanPostProcessor.postProcessAfterInitialization, beanName:student, bean:Student(id=99, name=张三)
INFO  [main] cn.ganlixin.Test - 测试程序获取到的student bean:Student(id=99, name=张三)
INFO  [main] cn.ganlixin.processor.MyDestructionAwareBeanPostProcessor - DestructionAwareBeanPostProcessor.postProcessBeforeDestruction, 
	beanName:student, bean:Student(id=99, name=张三)
INFO  [main] cn.ganlixin.entity.Student - DisposableBean.destory, this:Student(id=99, name=张三)
INFO  [main] cn.ganlixin.entity.Student - destroy-method, Student.clean, this:Student(id=99, name=张三)

  

十.总结

  看了上面这个输出结果,再结合下面这个图,基本就能掌握Bean的大致生命周期了。

  Spring Bean生命周期的各阶段介绍_第3张图片

 

   原文地址:https://www.cnblogs.com/-beyond/p/13188675.html

   

 

  

 

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