spring容器初始化bean和销毁bean之前进行一些操作的方法

柔光的暖阳◎ 2022-04-06 03:38 268阅读 0赞

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_8681467]

[http://blog.csdn.net/topwqp/article/details/8681497][http_blog.csdn.net_topwqp_article_details_8681497]

[http_blog.csdn.net_topwqp_article_details_8681467]: http://blog.csdn.net/topwqp/article/details/8681467
[http_blog.csdn.net_topwqp_article_details_8681497]: http://blog.csdn.net/topwqp/article/details/8681497