sprintboot中使用监听器

最新推荐文章于 2025-05-15 23:07:46 发布

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#springboot

本文介绍了一种在Spring Boot环境中监听Session和Application属性变化的方法，包括属性的增加、修改和删除，以及Session和Application的创建与销毁过程。

实例1

package com.cssl.listener;

import javax.servlet.ServletContextAttributeEvent;
import javax.servlet.ServletContextAttributeListener;
import javax.servlet.annotation.WebListener;
import javax.servlet.http.HttpSession;
import javax.servlet.http.HttpSessionAttributeListener;
import javax.servlet.http.HttpSessionBindingEvent;

/**
 * 监听session、application属性的增删改
 *
 */
//@WebListener
@Component//加入到springboot组件中
public class AttrListener implements HttpSessionAttributeListener, ServletContextAttributeListener {
	

	/**
     * @see 监听session属性新增
     */
    public void attributeAdded(HttpSessionBindingEvent se)  { 
         System.out.println("attributeAdded:"+se.getName()+"\t"+se.getValue());
    }   
    
    /**
     * @see 监听session属性修改
     */
    public void attributeReplaced(HttpSessionBindingEvent se)  { 
    	HttpSession session = se.getSession();
    	System.out.println("attributeReplaced before:"+se.getName()+"\t"+se.getValue());
    	System.out.println("attributeReplaced after:"+se.getName()+"\t"+session.getAttribute(se.getName()));
    }

	/**
     * @see 监听session属性删除
     */
    public void attributeRemoved(HttpSessionBindingEvent se)  { 
    	System.out.println("attributeRemoved:"+se.getName()+"\t"+se.getValue());
    }

	
    /**
     * @see ServletContextAttributeListener#attributeAdded(ServletContextAttributeEvent)
     */
    public void attributeAdded(ServletContextAttributeEvent scae)  { 
         // TODO Auto-generated method stub
    }

	/**
     * @see ServletContextAttributeListener#attributeRemoved(ServletContextAttributeEvent)
     */
    public void attributeRemoved(ServletContextAttributeEvent scae)  { 
         // TODO Auto-generated method stub
    }
    
    /**
     * @see ServletContextAttributeListener#attributeReplaced(ServletContextAttributeEvent)
     */
    public void attributeReplaced(ServletContextAttributeEvent scae)  { 
         // TODO Auto-generated method stub
    }
	
	
}

实例2：

package com.cssl.listener;

import java.util.ArrayList;
import java.util.List;

import javax.servlet.ServletContext;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import javax.servlet.annotation.WebListener;
import javax.servlet.http.HttpSession;
import javax.servlet.http.HttpSessionEvent;
import javax.servlet.http.HttpSessionListener;

/**
 * 监听session、application的创建和销毁
 *
 */
//@WebListener
@Component//加入到springboot组件中
public class MyListener implements ServletContextListener, HttpSessionListener {

	private ServletContext application;
	
    /**
     * Default constructor. 
     */
    public MyListener() {
        System.out.println("无参构造。。。");
    }

	/**
     * @see 创建session时候触发
     */
    public void sessionCreated(HttpSessionEvent se)  { 
    	HttpSession session = se.getSession();
    	session.setMaxInactiveInterval(30);
        System.out.println("sessionCreated id:"+session.getId());
    }

	/**
     * @see session销毁的时候触发
     */
    public void sessionDestroyed(HttpSessionEvent se)  { 
    	HttpSession session = se.getSession();
    	System.out.println("sessionDestroyed id:"+session.getId());
    	
    	//获得要注销的用户
    	String username = (String)session.getAttribute("username");
    	//所有在线用户
    	List<String> users = (List<String>)application.getAttribute("users");
    	if(users.contains(username)) {
    		//用户已在线
    		users.remove(username);
    	}
    	//application.setAttribute("users", users);
    }

	/**
     * @see application销毁
     */
    public void contextDestroyed(ServletContextEvent sce)  { 
         System.out.println("application销毁");
    }

	/**
     * @see application创建 
     */
    public void contextInitialized(ServletContextEvent sce)  { 
         System.out.println("application创建");
         application = sce.getServletContext();
         application.setAttribute("users", new ArrayList<String>());
    }
	
}