快捷導(dǎo)航

淺談Spring bean 生命周期驗(yàn)證

更新時(shí)間：2017年10月26日 10:13:24 作者：只會(huì)一點(diǎn)java

本篇文章主要介紹了淺談Spring bean 生命周期驗(yàn)證，小編覺得挺不錯(cuò)的，現(xiàn)在分享給大家，也給大家做個(gè)參考。一起跟隨小編過來看看吧

一、從源碼注釋看bean生命周期

從JDK源碼上看，BeanFactory實(shí)現(xiàn)類需要支持Bean的完整生命周期，完整的初始化方法及其標(biāo)準(zhǔn)順序（格式：接口方法）為:

1.BeanNameAware setBeanName 設(shè)置bean名稱
2.BeanClassLoaderAware setBeanClassLoader 設(shè)置bean類加載器
3.BeanFactoryAware setBeanFactory 設(shè)置bean工廠
4.EnvironmentAware setEnvironment 設(shè)置環(huán)境：profiles+properties
5.EmbeddedValueResolverAware setEmbeddedValueResolver 設(shè)置嵌入式值解析器
6.ResourceLoaderAware setResourceLoader 設(shè)置資源載入器，只適用于在應(yīng)用程序上下文中運(yùn)行
7.ApplicationEventPublisherAware setApplicationEventPublisher注入應(yīng)用事件發(fā)布器ApplicationEventPublisher
8.MessageSourceAware setMessageSource 設(shè)置國際化支持
9.ApplicationContextAware setApplicationContext 設(shè)置應(yīng)用上下文
10.ServletContextAware setServletContext 設(shè)置servlet上下文
11.BeanPostProcessors postProcessBeforeInitialization 執(zhí)行bean處理器前置方法
12.InitializingBean afterPropertiesSet 執(zhí)行初始化Bean設(shè)置完屬性后置方法
13.a custom init-method definition 執(zhí)行自定義初始化方法
14.BeanPostProcessors postProcessAfterInitialization 執(zhí)行bean處理器后置方法

銷毀順序：

1.DestructionAwareBeanPostProcessors postProcessBeforeDestruction 銷毀處理器的前置方法
2.DisposableBean destroy Bean銷毀回調(diào)方法
3.a custom destroy-method definition 用戶自定義銷毀方法

核心方法流程圖：

二、測試驗(yàn)證

2.1分析原理

前面說的17個(gè)步驟都可以測試，我們選取其中的8個(gè)步驟進(jìn)行測試如下：

初始化流程：

1.BeanNameAware setBeanName 設(shè)置bean名稱
3.BeanFactoryAware setBeanFactory 設(shè)置bean工廠
11.BeanPostProcessors postProcessBeforeInitialization 執(zhí)行bean處理器前置方法
12.InitializingBean afterPropertiesSet 執(zhí)行初始化Bean設(shè)置完屬性后置方法
13.a custom init-method definition 執(zhí)行自定義初始化方法
14.BeanPostProcessors postProcessAfterInitialization 執(zhí)行bean處理器后置方法

銷毀流程：

2.DisposableBean destroy Bean銷毀回調(diào)方法
3.a custom destroy-method definition 用戶自定義銷毀方法

2.2 代碼清單

1.構(gòu)建一個(gè)Person類，實(shí)現(xiàn)BeanFactoryAware, BeanNameAware, InitializingBean, DisposableBean接口。

package spring.ioc;

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 Person implements BeanFactoryAware, BeanNameAware, InitializingBean, DisposableBean {
  
  private String name;
  
  private String mobile;
   
  public Person() {
    super();
    System.out.println("[構(gòu)造器] 調(diào)用Person的構(gòu)造器實(shí)例化");
  }

  public String getName() {
    return name;
  }

  public void setName(String name) {
    System.out.println("[屬性注入] name="+name);
    this.name = name;
  }

  public String getMobile() {
    return mobile;
  }

  public void setMobile(String mobile) {
    System.out.println("[屬性注入] mobile="+mobile);
    this.mobile = mobile;
  }

  @Override
  public void destroy() throws Exception {
    System.out.println("[接口DisposableBean.destroy() ]");
  }

  @Override
  public void afterPropertiesSet() throws Exception {
    System.out.println("[接口InitializingBean.afterPropertiesSet() ]");
  }

  @Override
  public void setBeanName(String name) {
    System.out.println("[接口BeanNameAware.setBeanName() ]");
  }

  @Override
  public void setBeanFactory(BeanFactory beanFactory) throws BeansException {
    System.out.println("[接口BeanFactoryAware.setBeanFactory() ]");
  }

  public void myInit(){
    System.out.println("[init-method]調(diào)用<bean>的init-method屬性指定的初始化方法");
  }
  
  public void myDestory() {
    System.out.println("[destroy-method]調(diào)用<bean>的destroy-method屬性指定的銷毀方法");
  }

}

2.自定義工廠后處理器，復(fù)寫postProcessBeanFactory方法，獲取bean定義后添加屬性mobile=110

package spring.ioc;

import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.BeanDefinition;
import org.springframework.beans.factory.config.BeanFactoryPostProcessor;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;

/**
 * 
 * @ClassName:MyBeanFactoryPostProcessor
 * @Description:自定義工廠后處理器
 * @author diandian.zhang
 * @date 2017年10月25日下午7:14:09
 */
public class MyBeanFactoryPostProcessor implements BeanFactoryPostProcessor {

  public MyBeanFactoryPostProcessor() {
    super();
    System.out.println("[MyBeanFactoryPostProcessor工廠后處理器]BeanFactoryPostProcessor實(shí)現(xiàn)類構(gòu)造器??！");
  }

  @Override
  public void postProcessBeanFactory(ConfigurableListableBeanFactory arg0)
      throws BeansException {
    System.out.println("[MyBeanFactoryPostProcessor工廠后處理器]BeanFactoryPostProcessor.postProcessBeanFactory()獲取bean定義后添加屬性mobile=110");
    BeanDefinition bd = arg0.getBeanDefinition("person");
    bd.getPropertyValues().addPropertyValue("mobile", "110");
  }

}

3.自定義Bean后處理器，復(fù)寫postProcessBeforeInitialization和postProcessAfterInitialization2個(gè)方法，分別對(duì)應(yīng)初始化前后時(shí)的操作。

package spring.ioc;

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

/**
 * 
 * @ClassName:MyBeanPostProcessor
 * @Description:自定義Bean后處理器
 * @author diandian.zhang
 * @date 2017年10月25日下午7:03:53
 */
public class MyBeanPostProcessor implements BeanPostProcessor {

  public MyBeanPostProcessor() {
    super();
    System.out.println("這是BeanPostProcessor實(shí)現(xiàn)類構(gòu)造器??！");
  }

  /**
   * 
   * @Description 初始化前，處理器
   * @param bean
   * @param beanName
   * @return
   * @throws BeansException
   * @author diandian.zhang
   * @date 2017年10月25日下午7:07:02
   * @see org.springframework.beans.factory.config.BeanPostProcessor#postProcessBeforeInitialization(java.lang.Object, java.lang.String)
   */
  @Override
  public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
    System.out.println("BeanPostProcessor接口方法postProcessBeforeInitialization對(duì)屬性進(jìn)行更改！beanName="+beanName);
    return bean;
  }
  
  /**
   * 
   * @Description 初始化后，處理器
   * @param bean
   * @param beanName
   * @return
   * @throws BeansException
   * @author diandian.zhang
   * @date 2017年10月25日下午7:07:07
   * @see org.springframework.beans.factory.config.BeanPostProcessor#postProcessAfterInitialization(java.lang.Object, java.lang.String)
   */
  @Override
  public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
    System.out.println("BeanPostProcessor接口方法postProcessAfterInitialization對(duì)屬性進(jìn)行更改！beanName="+beanName);
    return bean;//注意，如果返回null,后續(xù)BeanPostProcessor不會(huì)再執(zhí)行
  }

  
}

4.自定義實(shí)例化bean后處理器適配器，復(fù)寫postProcessBeforeInstantiation、postProcessBeforeInstantiation、postProcessPropertyValues分別對(duì)應(yīng)實(shí)例化Bean前調(diào)用、實(shí)例化Bean后調(diào)用、設(shè)置某個(gè)屬性時(shí)調(diào)用

注意：InstantiationAwareBeanPostProcessorAdapter ，這里是實(shí)例化Instantiation，不是初始化Initialization?。?！

package spring.ioc;

import java.beans.PropertyDescriptor;

import org.springframework.beans.BeansException;
import org.springframework.beans.PropertyValues;
import org.springframework.beans.factory.config.InstantiationAwareBeanPostProcessorAdapter;

/**
 * 
 * @ClassName:MyInstantiationAwareBeanPostProcessor
 * @Description:BeanPostProcessor的子類，增加了更多自定方法
 * @author diandian.zhang
 * @date 2017年10月25日下午7:09:15
 */
public class MyInstantiationAwareBeanPostProcessor extends
    InstantiationAwareBeanPostProcessorAdapter {

  public MyInstantiationAwareBeanPostProcessor() {
    super();
    System.out.println("這是InstantiationAwareBeanPostProcessorAdapter實(shí)現(xiàn)類構(gòu)造器?。?);
  }

  // 接口方法、實(shí)例化Bean之前調(diào)用
  @Override
  public Object postProcessBeforeInstantiation(Class<?> beanClass,String beanName) throws BeansException {
    System.out.println("InstantiationAwareBeanPostProcessor調(diào)用postProcessBeforeInstantiation方法[實(shí)例化Bean之前調(diào)用 ]beanname="+beanName);
    return null;
  }

  // 接口方法、實(shí)例化Bean之后調(diào)用
  @Override
  public Object postProcessAfterInitialization(Object bean, String beanName)
      throws BeansException {
    System.out .println("InstantiationAwareBeanPostProcessor調(diào)用postProcessAfterInitialization方法[實(shí)例化Bean之后調(diào)用]beanname="+beanName);
    return bean;
  }

  // 接口方法、設(shè)置某個(gè)屬性時(shí)調(diào)用
  @Override
  public PropertyValues postProcessPropertyValues(PropertyValues pvs,
      PropertyDescriptor[] pds, Object bean, String beanName)
      throws BeansException {
    System.out.println("InstantiationAwareBeanPostProcessor調(diào)用postProcessPropertyValues方法 pvs="+pvs+",beanName="+beanName);
    return pvs;
  }
}

5.測試類，使用ClassPathXmlApplicationContext從xml中讀取bean配置文件生成applicationContext容器應(yīng)用上下文，這一步對(duì)應(yīng)容器初始化。第二部從應(yīng)用上下文中獲取bean。最后一步注冊(cè)一個(gè)關(guān)閉鉤子，在容器關(guān)閉時(shí)觸發(fā)。

package spring.ioc;

import org.junit.Test; 6 import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;10 
import spring.aop.xml.dao.Dao;

/**
 * 
 * @ClassName:IOCTest
 * @Description:測試類
 * @author diandian.zhang
 * @date 2017年10月25日下午4:42:01
 */
public class IOCTest {
  
  @Test
  public void iocPersonTest(){
    System.out.println("=============容器初始化======start=========");
    @SuppressWarnings("resource")
    ApplicationContext applicationContext = new ClassPathXmlApplicationContext("simple_spring_bean.xml");//源碼入口
    System.out.println("=============容器初始化=======end========");
    System.out.println("=============獲取person bean====start=======");
    Person person = applicationContext.getBean("person",Person.class);//獲取Bean
    System.out.println("=============獲取person bean====end=======,person類名="+person.getClass().getName());
    System.out.println("=============注冊(cè)關(guān)閉鉤子，關(guān)閉容器（JVM shutdown）時(shí)觸發(fā)鉤子！================");
    ((ClassPathXmlApplicationContext)applicationContext).registerShutdownHook();
  }
}

直接運(yùn)行，結(jié)果如下：

=============容器初始化======start=========
log4j:WARN No appenders could be found for logger (org.springframework.core.env.StandardEnvironment).
log4j:WARN Please initialize the log4j system properly.
[MyBeanFactoryPostProcessor工廠后處理器]BeanFactoryPostProcessor實(shí)現(xiàn)類構(gòu)造器！！
[MyBeanFactoryPostProcessor工廠后處理器]BeanFactoryPostProcessor.postProcessBeanFactory()獲取bean定義后添加屬性mobile=110
這是BeanPostProcessor實(shí)現(xiàn)類構(gòu)造器?。?
這是InstantiationAwareBeanPostProcessorAdapter實(shí)現(xiàn)類構(gòu)造器??！
InstantiationAwareBeanPostProcessor調(diào)用postProcessBeforeInstantiation方法[實(shí)例化Bean之前調(diào)用 ]beanname=person
[構(gòu)造器] 調(diào)用Person的構(gòu)造器實(shí)例化
InstantiationAwareBeanPostProcessor調(diào)用postProcessPropertyValues方法 pvs=PropertyValues: length=2; bean property 'mobile'; bean property 'name',beanName=person
[屬性注入] mobile=110
[屬性注入] name=張三
[接口BeanNameAware.setBeanName() ]
[接口BeanFactoryAware.setBeanFactory() ]
BeanPostProcessor接口方法postProcessBeforeInitialization對(duì)屬性進(jìn)行更改！beanName=person
[接口InitializingBean.afterPropertiesSet() ]
[init-method]調(diào)用<bean>的init-method屬性指定的初始化方法
BeanPostProcessor接口方法postProcessAfterInitialization對(duì)屬性進(jìn)行更改！beanName=person
InstantiationAwareBeanPostProcessor調(diào)用postProcessAfterInitialization方法[實(shí)例化Bean之后調(diào)用]beanname=person
=============容器初始化=======end========
=============獲取person bean====start=======
=============獲取person bean====end=======,person類名=spring.ioc.Person
=============注冊(cè)關(guān)閉鉤子，關(guān)閉容器（JVM shutdown）時(shí)觸發(fā)鉤子！================
[接口DisposableBean.destroy() ]
[destroy-method]調(diào)用<bean>的destroy-method屬性指定的銷毀方法

總結(jié)流程：