关于在spring 容器初始化 bean 和销毁前所做的操作定义方式有三种

关于在spring 容器初始化 bean 和销毁前所做的操作定义方式有三种

第一种：通过@PostConstruct 和 @PreDestroy 方法 实现初始化和销毁bean之前进行的操作

第二种是：通过 在xml中定义init-method 和 destory-method方法

在xml中配置 init-method和 destory-method方法

只是定义spring 容器在初始化bean 和容器销毁之前的所做的操作

基于xml的配置只是一种方式：

直接上xml中配置文件:

<bean id="personService" class="com.myapp.core.beanscope.PersonService" scope="singleton"  init-method="init"  destroy-method="cleanUp">  

</bean>  

定义PersonService类：

package com.myapp.core.beanscope;  


public class PersonService  {  
   private String  message;  

    public String getMessage() {  
        return message;  
    }  

    public void setMessage(String message) {  
        this.message = message;  
    }  



    public void init(){  
        System.out.println("init");  
    }  
    //  how  validate the  destory method is  a question  
    public void  cleanUp(){  
        System.out.println("cleanUp");  
    }  
}  

相应的测试类：

package com.myapp.core.beanscope;  

import org.springframework.context.support.AbstractApplicationContext;  
import org.springframework.context.support.ClassPathXmlApplicationContext;  

public class MainTest {  
  public static void main(String[] args) {  

      AbstractApplicationContext  context =new  ClassPathXmlApplicationContext("SpringBeans.xml");  

    PersonService  person = (PersonService)context.getBean("personService");  

    person.setMessage("hello  spring");  

    PersonService  person_new = (PersonService)context.getBean("personService");  

    System.out.println(person.getMessage());  
    System.out.println(person_new.getMessage());  
    context.registerShutdownHook();  


}  
}   

测试结果：

init
hello  spring
hello  spring
cleanUp

可以看出 init 方法和 clean up方法都已经执行了。



context.registerShutdownHook(); 是一个钩子方法，当jvm关闭退出的时候会调用这个钩子方法，在设计模式之 模板模式中 通过在抽象类中定义这样的钩子方法由实现类进行实现，这里的实现类是AbstractApplicationContext，这是spring 容器优雅关闭的方法。

第三种是： 通过bean实现InitializingBean和 DisposableBean接口

1：定义相应类实现InitializingBean ,DisposableBean 接口

package com.myapp.core.annotation.init;  

import javax.annotation.PostConstruct;  
import javax.annotation.PreDestroy;  

import org.springframework.beans.factory.DisposableBean;  
import org.springframework.beans.factory.InitializingBean;  

public class PersonService  implements InitializingBean,DisposableBean{  

    private String  message;  

    public String getMessage() {  
        return message;  
    }  

    public void setMessage(String message) {  
        this.message = message;  
    }  

    @Override  
    public void destroy() throws Exception {  
        // TODO Auto-generated method stub  
        System.out.println("I'm  init  method  using implements InitializingBean interface...."+message);  

    }  

    @Override  
    public void afterPropertiesSet() throws Exception {  
        // TODO Auto-generated method stub  
        System.out.println("I'm  init  method  using implements DisposableBean interface...."+message);  

    }  


}  

2：定义相应的配置文件:

<?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:context="http://www.springframework.org/schema/context"  
xsi:schemaLocation="http://www.springframework.org/schema/beans  
http://www.springframework.org/schema/beans/spring-beans-3.1.xsd  
http://www.springframework.org/schema/context  
http://www.springframework.org/schema/context/spring-context-3.1.xsd">  

<!-- <context:component-scan  base-package="com.myapp.core.jsr330"/> -->  

<!-- <context:annotation-config /> -->  


<!-- <bean class="org.springframework.context.annotation.CommonAnnotationBeanPostProcessor" />  
<bean id="personService" class="com.myapp.core.annotation.init.PersonService">  
          <property name="message" value="123"></property>  
</bean>  
 -->  

<bean id="personService" class="com.myapp.core.annotation.init.PersonService">  
          <property name="message" value="123"></property>  
</bean>  

</beans>  

3：测试类：

package com.myapp.core.annotation.init;  

import org.springframework.context.ApplicationContext;  
import org.springframework.context.support.AbstractApplicationContext;  
import org.springframework.context.support.ClassPathXmlApplicationContext;  

public class MainTest {  

    public static void main(String[] args) {  

        AbstractApplicationContext  context = new ClassPathXmlApplicationContext("resource/annotation.xml");  

        PersonService   personService  =  (PersonService)context.getBean("personService");  

             context.registerShutdownHook();  
    }  

}  

4：输出测试结果：

I'm  init  method  using implements DisposableBean interface....123  
三月 16, 2013 5:06:34 下午 org.springframework.context.support.AbstractApplicationContext doClose  
INFO: Closing org.springframework.context.support.ClassPathXmlApplicationContext@205756: startup date [Sat Mar 16 17:06:30 CST 2013]; root of context hierarchy  
I'm  init  method  using implements InitializingBean interface....123