（002）spring容器中bean初始化、销毁时执行的方法及其3种实现方式
分类:
IT文章
•
2022-05-21 21:29:13
spring容器中bean初始化或者销毁时会执行一些方法，有3种实现方式。
1、实现InitializingBean、DisposableBean接口，在bean的属性设置后和bean销毁时分别执行afterPropertiesSet和destroy方法
pom.xml文件
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<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.edu.spring</groupId>
<artifactId>spring</artifactId>
<version>1.0.0</version>
<name>spring</name>
<!-- FIXME change it to the project's website -->
<url>http://www.example.com</url>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<maven.compiler.source>1.8</maven.compiler.source>
<maven.compiler.target>1.8</maven.compiler.target>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>4.3.2.RELEASE</version>
</dependency>
</dependencies>
</project>
View Code
Cat.java
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package com.edu.spring;
import org.springframework.beans.factory.DisposableBean;
import org.springframework.beans.factory.InitializingBean;
public class Cat implements InitializingBean,DisposableBean{
@Override
public void afterPropertiesSet() throws Exception {
// TODO Auto-generated method stub
System.out.println("-----------afterPropertiesSet--------------");
}
@Override
public void destroy() throws Exception {
// TODO Auto-generated method stub
System.out.println("-----------destroy--------------");
}
}
View Code
MyConfig.java
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package com.edu.spring;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
@Configuration
public class MyConfig {
@Bean
public Cat createCat(){
return new Cat();
}
}
View Code
App.java
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package com.edu.spring;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
public class App
{
public static void main( String[] args )
{
AnnotationConfigApplicationContext context=new AnnotationConfigApplicationContext(MyConfig.class);
System.out.println(context.getBean(Cat.class));
context.close();
}
}
View Code
运行结果如下：
2、在@Bean注解中用initMethod和destroyMethod两个属性指定实体类中的两个方法，这两个方法分别在bean初始化和销毁时候执行
Dog.java
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package com.edu.spring;
public class Dog {
public void init(){
System.out.println("----------Dog init---------");
}
public void destroy(){
System.out.println("----------Dog destroy---------");
}
}
View Code
MyConfig.java
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package com.edu.spring;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
@Configuration
public class MyConfig {
@Bean(initMethod="init",destroyMethod="destroy")
public Dog createDog(){
return new Dog();
}
}
View Code
App.java
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package com.edu.spring;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
public class App
{
public static void main( String[] args )
{
AnnotationConfigApplicationContext context=new AnnotationConfigApplicationContext(MyConfig.class);
System.out.println(context.getBean(Dog.class));
context.close();
}
}
View Code
运行结果如下：
3、在实体类中方法上面分别添加@PostConstruct和@PreDestroy注解，分别指定初始化和销毁方法
Animal.java
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package com.edu.spring;
import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;
public class Animal {
@PostConstruct
public void initial(){
System.out.println("-------initial---------");
}
@PreDestroy
public void close(){
System.out.println("---------close---------");
}
}
View Code
MyConfig.java
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package com.edu.spring;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
@Configuration
public class MyConfig {
@Bean
public Animal createAniaml(){
return new Animal();
}
}
View Code
App.java
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package com.edu.spring;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
public class App
{
public static void main( String[] args )
{
AnnotationConfigApplicationContext context=new AnnotationConfigApplicationContext(MyConfig.class);
System.out.println(context.getBean(Animal.class));
context.close();
}
}
View Code
运行结果如下：
