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浅谈Spring bean 生命周期验证

2019年07月19日  | 移动技术网IT编程  | 我要评论

一、从源码注释看bean生命周期

从jdk源码上看,beanfactory实现类需要支持bean的完整生命周期,完整的初始化方法及其标准顺序(格式:接口 方法)为:

1.beannameaware setbeanname 设置bean名称
2.beanclassloaderaware setbeanclassloader 设置bean类加载器
3.beanfactoryaware setbeanfactory 设置bean工厂
4.environmentaware setenvironment 设置环境:profiles+properties
5.embeddedvalueresolveraware setembeddedvalueresolver 设置嵌入式值解析器
6.resourceloaderaware setresourceloader 设置资源载入器,只适用于在应用程序上下文中运行
7.applicationeventpublisheraware setapplicationeventpublisher注入应用事件发布器applicationeventpublisher
8.messagesourceaware setmessagesource 设置国际化支持
9.applicationcontextaware setapplicationcontext 设置应用上下文
10.servletcontextaware setservletcontext 设置servlet上下文
11.beanpostprocessors postprocessbeforeinitialization 执行bean处理器前置方法
12.initializingbean afterpropertiesset 执行初始化bean设置完属性后置方法
13.a custom init-method definition 执行自定义初始化方法
14.beanpostprocessors postprocessafterinitialization 执行bean处理器后置方法

销毁顺序:

1.destructionawarebeanpostprocessors postprocessbeforedestruction 销毁处理器的前置方法
2.disposablebean destroy bean销毁回调方法
3.a custom destroy-method definition 用户自定义销毁方法

核心方法流程图:

二、测试验证

2.1分析原理

前面说的17个步骤都可以测试,我们选取其中的8个步骤进行测试如下:

初始化流程:

1.beannameaware setbeanname 设置bean名称
3.beanfactoryaware setbeanfactory 设置bean工厂
11.beanpostprocessors postprocessbeforeinitialization 执行bean处理器前置方法
12.initializingbean afterpropertiesset 执行初始化bean设置完属性后置方法
13.a custom init-method definition 执行自定义初始化方法
14.beanpostprocessors postprocessafterinitialization 执行bean处理器后置方法

销毁流程:

2.disposablebean destroy bean销毁回调方法
3.a custom destroy-method definition 用户自定义销毁方法

 2.2 代码清单

 1.构建一个person类,实现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("[构造器] 调用person的构造器实例化");
  }

  public string getname() {
    return name;
  }

  public void setname(string name) {
    system.out.println("[属性注入] name="+name);
    this.name = name;
  }

  public string getmobile() {
    return mobile;
  }

  public void setmobile(string mobile) {
    system.out.println("[属性注入] 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]调用<bean>的init-method属性指定的初始化方法");
  }
  
  public void mydestory() {
    system.out.println("[destroy-method]调用<bean>的destroy-method属性指定的销毁方法");
  }

}

2.自定义工厂后处理器,复写postprocessbeanfactory方法,获取bean定义后添加属性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:自定义工厂后处理器
 * @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工厂后处理器]beanfactorypostprocessor实现类构造器!!");
  }

  @override
  public void postprocessbeanfactory(configurablelistablebeanfactory arg0)
      throws beansexception {
    system.out.println("[mybeanfactorypostprocessor工厂后处理器]beanfactorypostprocessor.postprocessbeanfactory()获取bean定义后添加属性mobile=110");
    beandefinition bd = arg0.getbeandefinition("person");
    bd.getpropertyvalues().addpropertyvalue("mobile", "110");
  }

}

3.自定义bean后处理器,复写postprocessbeforeinitialization和postprocessafterinitialization2个方法,分别对应初始化前后时的操作。

package spring.ioc;

import org.springframework.beans.beansexception;
import org.springframework.beans.factory.config.beanpostprocessor;

/**
 * 
 * @classname:mybeanpostprocessor
 * @description:自定义bean后处理器
 * @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("这是beanpostprocessor实现类构造器!!");
  }

  /**
   * 
   * @description 初始化前,处理器
   * @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对属性进行更改!beanname="+beanname);
    return bean;
  }
  
  /**
   * 
   * @description 初始化后,处理器
   * @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对属性进行更改!beanname="+beanname);
    return bean;//注意,如果返回null,后续beanpostprocessor不会再执行
  }

  
}

4.自定义实例化bean后处理器适配器,复写postprocessbeforeinstantiation、postprocessbeforeinstantiation、postprocesspropertyvalues分别对应实例化bean前调用、实例化bean后调用、设置某个属性时调用

注意:instantiationawarebeanpostprocessoradapter ,这里是实例化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的子类,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("这是instantiationawarebeanpostprocessoradapter实现类构造器!!");
  }

  // 接口方法、实例化bean之前调用
  @override
  public object postprocessbeforeinstantiation(class<?> beanclass,string beanname) throws beansexception {
    system.out.println("instantiationawarebeanpostprocessor调用postprocessbeforeinstantiation方法[实例化bean之前调用 ]beanname="+beanname);
    return null;
  }

  // 接口方法、实例化bean之后调用
  @override
  public object postprocessafterinitialization(object bean, string beanname)
      throws beansexception {
    system.out .println("instantiationawarebeanpostprocessor调用postprocessafterinitialization方法[实例化bean之后调用]beanname="+beanname);
    return bean;
  }

  // 接口方法、设置某个属性时调用
  @override
  public propertyvalues postprocesspropertyvalues(propertyvalues pvs,
      propertydescriptor[] pds, object bean, string beanname)
      throws beansexception {
    system.out.println("instantiationawarebeanpostprocessor调用postprocesspropertyvalues方法 pvs="+pvs+",beanname="+beanname);
    return pvs;
  }
}

5.测试类,使用classpathxmlapplicationcontext从xml中读取bean配置文件生成applicationcontext容器应用上下文,这一步对应容器初始化。第二部从应用上下文中获取bean。最后一步注册一个关闭钩子,在容器关闭时触发。

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:测试类
 * @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");//源码入口
    system.out.println("=============容器初始化=======end========");
    system.out.println("=============获取person bean====start=======");
    person person = applicationcontext.getbean("person",person.class);//获取bean
    system.out.println("=============获取person bean====end=======,person类名="+person.getclass().getname());
    system.out.println("=============注册关闭钩子,关闭容器(jvm shutdown)时触发钩子!================");
    ((classpathxmlapplicationcontext)applicationcontext).registershutdownhook();
  }
}

直接运行,结果如下:

=============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工厂后处理器]beanfactorypostprocessor实现类构造器!!
[mybeanfactorypostprocessor工厂后处理器]beanfactorypostprocessor.postprocessbeanfactory()获取bean定义后添加属性mobile=110
这是beanpostprocessor实现类构造器!!
这是instantiationawarebeanpostprocessoradapter实现类构造器!!
instantiationawarebeanpostprocessor调用postprocessbeforeinstantiation方法[实例化bean之前调用 ]beanname=person
[构造器] 调用person的构造器实例化
instantiationawarebeanpostprocessor调用postprocesspropertyvalues方法 pvs=propertyvalues: length=2; bean property 'mobile'; bean property 'name',beanname=person
[属性注入] mobile=110
[属性注入] name=张三
[接口beannameaware.setbeanname() ]
[接口beanfactoryaware.setbeanfactory() ]
beanpostprocessor接口方法postprocessbeforeinitialization对属性进行更改!beanname=person
[接口initializingbean.afterpropertiesset() ]
[init-method]调用<bean>的init-method属性指定的初始化方法
beanpostprocessor接口方法postprocessafterinitialization对属性进行更改!beanname=person
instantiationawarebeanpostprocessor调用postprocessafterinitialization方法[实例化bean之后调用]beanname=person
=============容器初始化=======end========
=============获取person bean====start=======
=============获取person bean====end=======,person类名=spring.ioc.person
=============注册关闭钩子,关闭容器(jvm shutdown)时触发钩子!================
[接口disposablebean.destroy() ]
[destroy-method]调用<bean>的destroy-method属性指定的销毁方法

总结流程:

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