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Spring学习笔记之bean生命周期

时间：2021-03-04 10:09     来源/作者：小崔

前言

上一篇文章主要学习了下bean的配置、注入、自定义属性编辑器，今天来熟悉bean的生命周期。

任何一个事物都有自己的生命周期，生命的开始、生命中、生命结束。大家最熟悉的应该是servlet 的生命周期吧。和 servlet 一样 spring bean 也有自己的生命周期。

在开发中生命周期是一个很常见的名词，基本每种编程语言都能找到与它关联的。关于bean的生命周期我在网上也找了好多，基本都差不多。这里我主要是想通过代码来验证，毕竟学的知识都是一样的，都是学的java，最重要的是动手练习，这样印象更深。

下面是它生命周期的描述，我们通过demo来进行验证。

下图是它执行的顺序。

Spring学习笔记之bean生命周期

Spring学习笔记之bean生命周期

一、创建liftcycle类实现beanfactoryaware,beannameaware,initializingbean,disposablebean,applicationcontextaware5个接口方法

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package cuiyw.spring.service;
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;
import org.springframework.context.applicationcontext;
import org.springframework.context.applicationcontextaware;
public class lifecycle implements beanfactoryaware,beannameaware,initializingbean,disposablebean,applicationcontextaware{
 
 private string name;
 public string getname() {
 system.out.println("getname name="+name);
 return name;
 }
 public void setname(string name) {
  system.out.println("setname name="+name);
 this.name = name;
 }
 public void afterpropertiesset() throws exception {
 // todo auto-generated method stub
  system.out.println("initializingbean.afterpropertiesset()");
 }
 public void setbeanname(string arg0) {
 // todo auto-generated method stub
 system.out.println("beannameaware.setbeanname");
 }
 public void setbeanfactory(beanfactory arg0) throws beansexception {
 // todo auto-generated method stub
 system.out.println("beanfactoryaware.setbeanfactory");
 }
 public void destroy() throws exception {
 // todo auto-generated method stub
 system.out.println("disposablebean.destroy");
 }
 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属性指定的初始化方法");
 }
 public void setapplicationcontext(applicationcontext arg0) throws beansexception {
 // todo auto-generated method stub
  system.out.println("applicationcontextaware.setapplicationcontext");
 }
}

二、注册instantiationawarebeanpostprocessor接口

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package cuiyw.spring.service;
 
import java.beans.propertydescriptor;
 
import org.springframework.beans.beansexception;
import org.springframework.beans.propertyvalues;
import org.springframework.beans.factory.config.instantiationawarebeanpostprocessor;
 
public class myinstantiationawarebeanpostprocessor implements instantiationawarebeanpostprocessor{
 public object postprocessafterinitialization(object bean, string beanname) throws beansexception {
 // todo auto-generated method stub
 system.out.println("instantiationawarebeanpostprocessor.postprocessafterinitialization");
 return bean;
 }
 public object postprocessbeforeinitialization(object bean, string beanname) throws beansexception {
 // todo auto-generated method stub
 system.out.println("instantiationawarebeanpostprocessor.postprocessbeforeinitialization");
 return bean;
 }
 public boolean postprocessafterinstantiation(object bean, string beanname) throws beansexception {
 // todo auto-generated method stub
 system.out.println("instantiationawarebeanpostprocessor.postprocessafterinstantiation");
 return true;
 }
 public object postprocessbeforeinstantiation(class<?> beanclass, string beanname) throws beansexception {
 // todo auto-generated method stub
 system.out.println("instantiationawarebeanpostprocessor.postprocessbeforeinstantiation");
 return null;
 }
 public propertyvalues postprocesspropertyvalues(propertyvalues pvs, propertydescriptor[] pds, object bean,
  string beanname) throws beansexception {
 // todo auto-generated method stub
 system.out.println("instantiationawarebeanpostprocessor.postprocesspropertyvalues");
 return pvs;
 }
}

三、注册beanpostprocessor接口

其实instantiationawarebeanpostprocessor继承beanpostprocessor，所以在上面我也实现了beanpostprocessor接口的方法

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package cuiyw.spring.service;
import org.springframework.beans.beansexception;
import org.springframework.beans.factory.config.beanpostprocessor;
public class mybeanpostprocessor implements beanpostprocessor {
 public object postprocessafterinitialization(object bean, string beanname) throws beansexception {
 // todo auto-generated method stub
 system.out.println("beanpostprocessor.postprocessafterinitialization ");
 return bean;
 }
 public object postprocessbeforeinitialization(object bean, string beanname) throws beansexception {
 // todo auto-generated method stub
 system.out.println("beanpostprocessor.postprocessbeforeinitialization");
 return bean;
 }
}

四、注册beanfactorypostprocessor接口

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package cuiyw.spring.service;
import org.springframework.beans.beansexception;
import org.springframework.beans.factory.config.beanfactorypostprocessor;
import org.springframework.beans.factory.config.configurablelistablebeanfactory;
public class mybeanfactorypostprocessor implements beanfactorypostprocessor {
 public void postprocessbeanfactory(configurablelistablebeanfactory arg0) throws beansexception {
 // todo auto-generated method stub
 system.out.println("beanfactorypostprocessor.postprocessbeanfactory");
 }
}

五、在上下文中配置

这里还是在上一个博客demo的基础上进行修改，为了有其他干扰，我先把service去掉了。

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<?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="beanpostprocessor" class="cuiyw.spring.service.mybeanpostprocessor"></bean>
<bean id="instantiationawarebeanpostprocessor" class="cuiyw.spring.service.myinstantiationawarebeanpostprocessor"></bean>
<bean id="beanfactorypostprocessor" class="cuiyw.spring.service.mybeanfactorypostprocessor"></bean>
<bean id="lifecycle" class="cuiyw.spring.service.lifecycle" init-method="myinit" destroy-method="mydestory">
<property name="name" value="cuiyw1"></property>
</bean>
</beans>

六、在main中使用bean

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package cuiyw.springaop;
 
import org.springframework.beans.factory.beanfactory;
import org.springframework.context.applicationcontext;
import org.springframework.context.support.classpathxmlapplicationcontext;
 
import cuiyw.spring.iservice.iservice;
import cuiyw.spring.service.lifecycle;
 
public class app
{
 public static void main( string[] args )
 {
 applicationcontext context=new classpathxmlapplicationcontext(new string[]{"applicationcontext.xml"});
 beanfactory factory=context;
 lifecycle lifecycle=factory.getbean("lifecycle",lifecycle.class);
 lifecycle.setname("cuiyw2");
  system.out.println("lifecycle.name="+lifecycle.getname());
 ((classpathxmlapplicationcontext)factory).registershutdownhook();
 /*service=(iservice)factory.getbean("servicea");
 service.service("cuiyw servicea");
 service=(iservice)factory.getbean("serviceimpl");
 service.service("cuiyw serviceimpl"); */
 }
}

七、输入打印结果

可以发现输出的顺序和上面图的顺序基本一致。

Spring学习笔记之bean生命周期

总结

以上就是这篇文章的全部内容了，希望本文的内容对大家的学习或者工作具有一定的参考学习价值，如果有疑问大家可以留言交流，谢谢大家对服务器之家的支持。

原文链接：http://www.cnblogs.com/5ishare/p/8030038.html

标签：
spring Bean 生命周期 

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