Copyright: https://blog.csdn.net/xichengqc/article/details/87368213
Today, the difference between research and interceptor's filter, see springboot integrated listener, the way to write a small demo statistical functions to achieve a number of online users.
Code management tools: springboot + maven3
- pom file
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
- Write 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();
}
}
- Registration 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;
}
}
- Write 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;
}
}
Start the project, visit: HTTP: // localhost:? 8080 / userName = the Login test01
open another browser: HTTP: // localhost: 8080 / userName = Test02 the Login?
Refresh the first page
of code github Address: HTTPS: // github.com/xichengxml/woodencottage/tree/master/190125-listener