spring容器初始化bean和销毁bean之前进行一些操作的方法

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，通过在xml中定义init-method和destory-method方法

第二种，通过bean实现InitializingBean和 DisposableBean接口

第三种，通过Spring @PostConstruct和@PreDestroy方法

一.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。

1.xml中配置文件

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:context="http://www.springframework.org/schema/context" xmlns:p="http://www.springframework.org/schema/p"
	xmlns:mvc="http://www.springframework.org/schema/mvc" 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-4.1.xsd
                    http://www.springframework.org/schema/context
                    http://www.springframework.org/schema/context/spring-context-4.1.xsd
                    http://www.springframework.org/schema/mvc
                    http://www.springframework.org/schema/mvc/spring-mvc-4.1.xsd
                    ">

    <bean id="testService" class="com.bijian.study.service.impl.TestService" init-method="afterPropertiesSet" destroy-method="destroy">  
          <property name="message" value="123"></property>  
	</bean>
	
    <mvc:annotation-driven></mvc:annotation-driven>
    
    <bean id="viewResolver" class="org.springframework.web.servlet.view.UrlBasedViewResolver">   
        <property name="viewClass"  
            value="org.springframework.web.servlet.view.JstlView" />   
        <property name="prefix" value="/WEB-INF/views" />
        <property name="suffix" value=".jsp" />   
    </bean>
</beans>

2.定义TestService类

package com.bijian.study.service.impl;

public class TestService {

    private String  message;  
  
    public String getMessage() {  
        return message;  
    }  
  
    public void setMessage(String message) {  
        this.message = message;  
    }
    
    public void afterPropertiesSet() throws Exception {
        System.out.println("I'm  init  method  using  @PostConstrut...."+message);
    }  

    public void destroy() throws Exception {
        System.out.println("I'm  destory method  using  @PreDestroy....."+message);
    }
}

3.相应的测试类

package com.bijian.study.test;

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

import com.bijian.study.service.impl.TestService;

public class MainTest {

    public static void main(String[] args) {
        
        try {
            AbstractApplicationContext context = new ClassPathXmlApplicationContext("file:D:/develop/eclipse/workspace/SpringMVC/WebContent/WEB-INF/springMVC-servlet.xml");  
            
            TestService testService  =  (TestService)context.getBean("testService");
            
            System.out.println(testService.getMessage());
            //testService.destroy();
            context.registerShutdownHook();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

运行结果：

I'm  init  method  using  @PostConstrut....123
123
I'm  destory method  using  @PreDestroy.....123

可以看出init-method方法和destroy-method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。

二.通过bean实现InitializingBean和 DisposableBean接口

1.xml中配置文件

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:context="http://www.springframework.org/schema/context" xmlns:p="http://www.springframework.org/schema/p"
	xmlns:mvc="http://www.springframework.org/schema/mvc" 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-4.1.xsd
                    http://www.springframework.org/schema/context
                    http://www.springframework.org/schema/context/spring-context-4.1.xsd
                    http://www.springframework.org/schema/mvc
                    http://www.springframework.org/schema/mvc/spring-mvc-4.1.xsd
                    ">

    <bean id="testService" class="com.bijian.study.service.impl.TestService">  
          <property name="message" value="123"></property>  
	</bean>
	
    <mvc:annotation-driven></mvc:annotation-driven>
    
    <bean id="viewResolver" class="org.springframework.web.servlet.view.UrlBasedViewResolver">   
        <property name="viewClass"  
            value="org.springframework.web.servlet.view.JstlView" />   
        <property name="prefix" value="/WEB-INF/views" />
        <property name="suffix" value=".jsp" />   
    </bean>
</beans>

2.定义TestService类

package com.bijian.study.service.impl;

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

public class TestService implements InitializingBean,DisposableBean{  
    
    private String  message;  
  
    public String getMessage() {  
        return message;  
    }  
  
    public void setMessage(String message) {  
        this.message = message;  
    }  

    public void afterPropertiesSet() throws Exception {
        System.out.println("I'm  init  method  using  @PostConstrut...."+message);
    }  

    public void destroy() throws Exception {
        System.out.println("I'm  destory method  using  @PreDestroy....."+message);
    }
}

3.测试类同上，运行测试类。

运行结果：

I'm  init  method  using  @PostConstrut....123
123
I'm  destory method  using  @PreDestroy.....123

三.通过Spring @PostConstruct和@PreDestroy方法

1.xml中配置文件

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:context="http://www.springframework.org/schema/context" xmlns:p="http://www.springframework.org/schema/p"
	xmlns:mvc="http://www.springframework.org/schema/mvc" 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-4.1.xsd
                    http://www.springframework.org/schema/context
                    http://www.springframework.org/schema/context/spring-context-4.1.xsd
                    http://www.springframework.org/schema/mvc
                    http://www.springframework.org/schema/mvc/spring-mvc-4.1.xsd
                    ">
    
	<context:component-scan base-package="com.bijian.study"></context:component-scan>   

    <bean id="testService" class="com.bijian.study.service.impl.TestService">  
          <property name="message" value="123"></property>  
	</bean>
	
	<context:annotation-config />
	
    <mvc:annotation-driven></mvc:annotation-driven>
    
    <bean id="viewResolver" class="org.springframework.web.servlet.view.UrlBasedViewResolver">   
        <property name="viewClass"  
            value="org.springframework.web.servlet.view.JstlView" />   
        <property name="prefix" value="/WEB-INF/views" />
        <property name="suffix" value=".jsp" />   
    </bean>
</beans>

其中<context:annotation-config />告诉spring 容器采用注解配置，扫描注解配置。

2.定义TestService类

package com.bijian.study.service.impl;

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

public class TestService {  
    
    private String  message;  
  
    public String getMessage() {  
        return message;  
    }  
  
    public void setMessage(String message) {  
        this.message = message;  
    }
    
    @PostConstruct
    public void afterPropertiesSet() throws Exception {
        System.out.println("I'm  init  method  using  @PostConstrut...."+message);
    }  
    
    @PreDestroy
    public void destroy() throws Exception {
        System.out.println("I'm  destory method  using  @PreDestroy....."+message);
    }
}

3.测试类同上，运行测试类。

运行结果：

I'm  init  method  using  @PostConstrut....123
123
I'm  destory method  using  @PreDestroy.....123

其中也可以通过申明加载org.springframework.context.annotation.CommonAnnotationBeanPostProcessor类来告诉Spring容器采用的常用解配置的方式，只需要修改配置文件为：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:context="http://www.springframework.org/schema/context" xmlns:p="http://www.springframework.org/schema/p"
	xmlns:mvc="http://www.springframework.org/schema/mvc" 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-4.1.xsd
                    http://www.springframework.org/schema/context
                    http://www.springframework.org/schema/context/spring-context-4.1.xsd
                    http://www.springframework.org/schema/mvc
                    http://www.springframework.org/schema/mvc/spring-mvc-4.1.xsd
                    ">
	
    <mvc:annotation-driven></mvc:annotation-driven>
    
    <bean id="viewResolver" class="org.springframework.web.servlet.view.UrlBasedViewResolver">   
        <property name="viewClass"  
            value="org.springframework.web.servlet.view.JstlView" />   
        <property name="prefix" value="/WEB-INF/views" />
        <property name="suffix" value=".jsp" />   
    </bean>
     
	<bean class="org.springframework.context.annotation.CommonAnnotationBeanPostProcessor" />
	<bean id="testService" class="com.bijian.study.service.impl.TestService">  
		<property name="message" value="123"></property>
	</bean>
</beans>

最后，Srping的bean可以通过注解配置方法注入。如下所示：

1.xml配置

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:context="http://www.springframework.org/schema/context" xmlns:p="http://www.springframework.org/schema/p"
	xmlns:mvc="http://www.springframework.org/schema/mvc" 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-4.1.xsd
                    http://www.springframework.org/schema/context
                    http://www.springframework.org/schema/context/spring-context-4.1.xsd
                    http://www.springframework.org/schema/mvc
                    http://www.springframework.org/schema/mvc/spring-mvc-4.1.xsd
                    ">
    
	<context:component-scan base-package="com.bijian.study"></context:component-scan>   

    <bean id="testService" class="com.bijian.study.service.impl.TestService">  
          <property name="message" value="123"></property>  
	</bean>
	
	<context:annotation-config />

    <mvc:annotation-driven></mvc:annotation-driven>
    
    <bean id="viewResolver" class="org.springframework.web.servlet.view.UrlBasedViewResolver">   
        <property name="viewClass"  
            value="org.springframework.web.servlet.view.JstlView" />   
        <property name="prefix" value="/WEB-INF/views" />
        <property name="suffix" value=".jsp" />   
    </bean>
</beans>

2.定义TestService类

package com.bijian.study.service.impl;

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

import org.springframework.stereotype.Service;

@Service("testService")
public class TestService { 
    
    private String  message;  
  
    public String getMessage() {  
        return message;  
    }
  
    public void setMessage(String message) {  
        this.message = message;  
    }
    
    @PostConstruct
    public void afterPropertiesSet() throws Exception {
        System.out.println("I'm  init  method  using  @PostConstrut...."+message);
    }  
    
    @PreDestroy
    public void destroy() throws Exception {
        System.out.println("I'm  destory method  using  @PreDestroy....."+message);
    }
}

参考文章：

http://blog.csdn.net/topwqp/article/details/8681467

http://blog.csdn.net/topwqp/article/details/8681497

spring容器初始化bean和销毁bean之前进行一些操作的方法

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