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

时间:2021-09-08 21:09:13

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

第三种是: 通过bean实现InitializingBean和 DisposableBean接口


下面演示通过  @PostConstruct 和 @PreDestory

1:定义相关的实现类:

package com.myapp.core.annotation.init;  

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

public class PersonService {

private String message;

public String getMessage() {
return message;
}

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

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

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

}
2:定义相关的配置文件:

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

</beans>


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

测试类:

package com.myapp.core.annotation.init;  

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

public class MainTest {

public static void main(String[] args) {

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

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

personService.dostory();
}

}
测试结果:

I'm  init  method  using  @PostConstrut....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 注解配置的方式:

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: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>



</beans>

同样可以得到以上测试的输出结果。