Spring InitializingBean and DisposableBean example

最新推荐文章于 2022-12-08 06:30:00 发布

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本文介绍 Spring 框架中 InitializingBean 和 DisposableBean 接口的作用，通过示例展示如何使用这两个接口来实现 Bean 的初始化和销毁操作，并探讨了更好的实践方法。

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In Spring, InitializingBean and DisposableBean are two marker interfaces, a useful way for Spring to perform certain actions upon bean initialization and destruction.

For bean implemented InitializingBean, it will run afterPropertiesSet() after all bean properties have been set.
For bean implemented DisposableBean, it will run destroy() after Spring container is released the bean.

Example

package org.kodejava.example.spring;
 
import org.springframework.beans.factory.DisposableBean;
import org.springframework.beans.factory.InitializingBean;
 
public class InitDisposeService
        implements InitializingBean, DisposableBean {
    
    /**
     * Do some processes.
     */
    public void doSomething() {
        System.out.println("InitDisposeService.doSomething");
    }
 
    /**
     * Initialize bean after property set.
     *
     * @throws Exception
     */
    @Override
    public void afterPropertiesSet() throws Exception {
        System.out.println("InitDisposeService.afterPropertiesSet");
    }
 
    /**
     * Clean-up bean when the context is closed.
     *
     * @throws Exception
     */
    @Override
    public void destroy() throws Exception {
        System.out.println("InitDisposeService.destroy");
    }
}

Here’s an example to show you how to use InitializingBeanand DisposableBean. A CustomerService bean to implement both InitializingBean and DisposableBean interface, and has a message property.

File : Spring-Customer.xml

<?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-3.0.xsd">

    <bean id="service" class="org.kodejava.example.spring.InitDisposeService"/>

</beans>

Run it

package org.kodejava.example.spring;
 
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
 
public class InitDisposeDemo {
    public static void main(String[] args) {
        ConfigurableApplicationContext context =
                new ClassPathXmlApplicationContext("InitDispose.xml");
 
        InitDisposeService service =
                (InitDisposeService) context.getBean("service");
        service.doSomething();
 
        context.close();
    }
}

The ConfigurableApplicationContext.close() will close the application context, releasing all resources and destroying all cached singleton beans. It’s use fordestroy() method demo purpose only :)

Output

InitDisposeService.afterPropertiesSet
InitDisposeService.doSomething
InitDisposeService.destroy

The afterPropertiesSet() method is called, after the message property is set; while the destroy() method is call after the context.close();

Thoughts…
I would not recommend to use InitializingBean and DisposableBean interface, because it will tight coupled your code to Spring. A better approach should be specifying theinit-method and destroy-method attributes in your bean configuration file. see http://blog.youkuaiyun.com/gloomuu/article/details/8588380