SpringBoot集成SessionListener统计在线用户人数

版权声明： https://blog.csdn.net/xichengqc/article/details/87368213

今天研究filter和interceptor的区别，看到了springboot集成listener，顺便写个小demo实现一个统计在线用户人数的功能。
代码管理工具：springboot + maven3

1. pom文件

<dependency>
	<groupId>org.springframework.boot</groupId>
	<artifactId>spring-boot-starter-web</artifactId>
</dependency>

2. 编写listener

package com.xicheng.listener.listener;

import javax.servlet.http.HttpSessionEvent;
import javax.servlet.http.HttpSessionListener;
import java.util.concurrent.atomic.AtomicInteger;

/**
 * @author xichengxml
 * @date 2019/2/15 14:44
 */
public class MySessionListener implements HttpSessionListener {

    public static AtomicInteger userCount = new AtomicInteger(0);

    /**
     * 用户登录，创建session，用户数增加
     * @param event
     */
    @Override
    public void sessionCreated(HttpSessionEvent event) {
        userCount.getAndIncrement();
    }

    /**
     * 用户下线，销毁session，用户数减少
     * @param event
     */
    @Override
    public void sessionDestroyed(HttpSessionEvent event) {
        userCount.getAndDecrement();
    }
}

3. 注册listener

package com.xicheng.listener.config;

import com.xicheng.listener.listener.MySessionListener;
import org.springframework.boot.web.servlet.ServletListenerRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

/**
 * @author xichengxml
 * @date 2019/2/15 14:42
 */
@Configuration
public class SpringMvcConfig implements WebMvcConfigurer{

    @Bean
    public ServletListenerRegistrationBean getListener() {
        ServletListenerRegistrationBean servletListenerRegistrationBean = new ServletListenerRegistrationBean();
        servletListenerRegistrationBean.setListener(new MySessionListener());
        return servletListenerRegistrationBean;
    }
}

4. 编写controller

package com.xicheng.listener.controller;

import com.xicheng.listener.listener.MySessionListener;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;
import java.util.concurrent.atomic.AtomicInteger;

/**
 * @author xichengxml
 * @date 2019/2/15 14:51
 */
@Controller
public class LoginController {

    @RequestMapping("/login")
    @ResponseBody
    public String login(String userName, HttpServletRequest request) {
        HttpSession httpSession = request.getSession(true);
        httpSession.setAttribute(userName, userName);
        AtomicInteger userCount = MySessionListener.userCount;
        return userName + "上线成功！当前在线人数： " + userCount;
    }

    @RequestMapping("/logout")
    @ResponseBody
    public String logout(String userName, HttpServletRequest request) {
        HttpSession httpSession = request.getSession(true);
        httpSession.removeAttribute(userName);
        httpSession.invalidate();
        AtomicInteger userCount = MySessionListener.userCount;
        return userName + "下线成功！当前在线人数：" + userCount;
    }
}

启动项目，访问：http://localhost:8080/login?userName=test01

打开另外一个浏览器：http://localhost:8080/login?userName=test02

刷新第一个页面

代码github地址：https://github.com/xichengxml/woodencottage/tree/master/190125-listener