Spring容器中的Bean几种初始化方法和销毁方法的先后顺序

Spring容器中的Bean是有生命周期，Spring 允许 Bean 在初始化完成后以及销毁前执行特定的操作。下面是常用的三种指定特定操作的方法：

• 通过实现InitializingBean/DisposableBean 接口来定制初始化之后/销毁之前的操作方法；
• 通过<bean> 元素的 init-method/destroy-method属性指定初始化之后 /销毁之前调用的操作方法；
• 在指定方法上加上@PostConstruct或@PreDestroy注解来制定该方法是在初始化之后还是销毁之前调用。

xml配置

<bean id="myInitializingBean" class="com.sf.sfbuy2.context.filter.MyInitializingBean">
</bean>
<bean id="myXmlBean" class="com.sf.sfbuy2.context.filter.MyXmlBean" init-method="initMethod" destroy-method="destroyMethod"></bean>
<bean id="myAnnoationBean" class="com.sf.sfbuy2.context.filter.MyAnnoationBean"></bean>

 方法一

import javax.annotation.PreDestroy;
import org.springframework.beans.factory.DisposableBean;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class MyInitializingBean implements InitializingBean,DisposableBean{
		  
	public MyInitializingBean(){  
		System.out.println("执行InitAndDestroySeqBean: 构造方法");  
	}  
	
	@Override  
	public void afterPropertiesSet() throws Exception {  
		System.out.println("执行InitAndDestroySeqBean: afterPropertiesSet");   
	}  
	
	
	@PreDestroy
	public void preDestroy()  {  
		System.out.println("执行InitAndDestroySeqBean: preDestroy");  
	}  
	
	@Override  
	public void destroy() throws Exception {  
		System.out.println("执行InitAndDestroySeqBean: destroy");  
	}  
	
	public static void main(String[] args) {  
		ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");  
		context.close();  
	}  
}

 方法二、

public class MyXmlBean{
		  
	public MyXmlBean(){  
		System.out.println("执行MyXmlBean: 构造方法");  
	}  
	public void initMethod() {  
		System.out.println("执行MyXmlBean: init-method");  
	} 
	public void destroyMethod() {  
		System.out.println("执行MyXmlBean: destroy-method");  
	}  
	
	public static void main(String[] args) {  
		ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");  
		context.close();  
	}  
}

 方法三、

import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class MyAnnoationBean{
		  
	public MyAnnoationBean(){  
		System.out.println("执行myAnnoationBean: 构造方法");  
	}  	
	@PostConstruct
	public void postConstructMethod() {  
		System.out.println("执行myAnnoationBean: postConstructMethod初始化方法");  
	} 
	
	@PreDestroy
	public void preDestroyMethod() {  
		System.out.println("执行myAnnoationBean: destroy-method销毁方法");  
	}  
	
	public static void main(String[] args) {  
		ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");  
		context.close();  
	}  
}

Bean在实例化的过程中：Constructor > @PostConstruct >InitializingBean > init-method

Bean在销毁的过程中：@PreDestroy > DisposableBean > destroy-method