利用session来进行系统在线人数统计和重复登录踢人，使用HttpSessionListener

Z时代
2024-01-10
分类：综合

@WebListener
public class SessionListener implements HttpSessionListener {
         public static HashMap sessionMap = new HashMap();
         public static int online = 0;
         @Override
         public void sessionCreated(HttpSessionEvent hse) {
           online ++;
         }
         @Override
         public void sessionDestroyed(HttpSessionEvent hse) {
           HttpSession session = hse.getSession();
           DelSession(session);
           online --;
         }
         private static synchronized void DelSession(HttpSession session) {
            if (session != null) {
               // 删除单一登录中记录的变量
              if(session.getAttribute("loginUser") != null){
                String username = (String) session.getAttribute("loginUser");
                SessionListener.sessionMap.remove(username);
              }
            }
         }}

2、登录时将sessionId放入map中

if (null != SessionListener.sessionMap.get(user.getDldm())) {
//将第一次登录用户的信息从map中移除
SessionListener.sessionMap.remove(username);
}
//本次登录用户添加到map中
SessionListener.sessionMap.put(user.getDldm(), request.getSession().getId());

3、创建登录拦截器

import com.winning.plat.common.exception.BaseException;
import org.apache.commons.lang.StringUtils;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerInterceptor;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
 * @ClassName LoginHandlerInterceptor
 * @Description TODO
 * @Author WJX
 * @Date 2020/6/30 9:40
 **/
@Component
public class LoginHandlerInterceptor implements HandlerInterceptor {
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        String username = (String) request.getSession().getAttribute("loginUser");
        String sessionId = request.getSession().getId();
        if(StringUtils.isNotBlank(username)){
            if (!StringUtils.equalsIgnoreCase((String) SessionListener.sessionMap.get(username),sessionId)) {
                throw new BaseException("该账号在别处登录,请重新登录",505);
            }
        }
        return true;
    }}

4、在webMvcConfig中配置

import com.winning.plat.common.config.AuthorizationInterceptor;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.Ordered;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.ViewControllerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
/**
* @Author: nxs@winning.com.cn
* 
* @Description:   MVC配置
* 
* @Date:  2018-06-25 17:05:39
*
*
 **/
@Configuration
public class WebMvcConfig extends WebMvcConfigurerAdapter {
    @Autowired
    private AuthorizationInterceptor authorizationInterceptor;
    @Autowired
    private LoginHandlerInterceptor loginHandlerInterceptor;
    @Override
    public void addViewControllers(ViewControllerRegistry registry) {
        registry.addViewController("/").setViewName("forward:/login.html");
        registry.setOrder(Ordered.HIGHEST_PRECEDENCE);
        super.addViewControllers(registry);
    }
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(authorizationInterceptor)
                // .addPathPatterns() 是配置需要拦截的路径
                .addPathPatterns("/**")
                // .excludePathPatterns() 用于排除拦截
                .excludePathPatterns("/") // 排除127.0.0.1进入登录页
                .excludePathPatterns("/login") // 排除127.0.0.1进入登录页
                .excludePathPatterns("/queryApp")
                .excludePathPatterns("/lib/**") // 排除静态文件
                .excludePathPatterns("/js/**")
                .excludePathPatterns("/img/**")
                .excludePathPatterns("/css/**")
                .excludePathPatterns("/*.html") // 排除登录页获取验证码接口
                .excludePathPatterns("/*.js") // 排除验证账号密码接口
                .excludePathPatterns("/*.css");
        registry.addInterceptor(loginHandlerInterceptor)
                .addPathPatterns("/**")
                .excludePathPatterns("/") // 排除127.0.0.1进入登录页
                .excludePathPatterns("/login") // 排除127.0.0.1进入登录页
                .excludePathPatterns("/queryApp")
                .excludePathPatterns("/lib/**") // 排除静态文件
                .excludePathPatterns("/js/**")
                .excludePathPatterns("/platcommon/**")
                .excludePathPatterns("/img/**")
                .excludePathPatterns("/css/**")
                .excludePathPatterns("/*.html") // 排除登录页获取验证码接口
                .excludePathPatterns("/*.js") // 排除验证账号密码接口
                .excludePathPatterns("/*.css");
    }}

5、在启动类上加入注解

@ServletComponentScan

6、登录时将用户名放入session中

session.setAttribute("loginName",username);

7、查询在线人数

/**
*查询在线人数
*/
@RequestMapping("/online")
public Object online() {
return "当前在线人数：" + MyHttpSessionListener.online + "人";
}
8、、退出登录

/**
* 退出登录
*/
@RequestMapping("/Logout")
public CommonResult Logout( HttpServletRequest request) {
logger.info("用户退出登录开始！");
HttpSession session = request.getSession(false);//防止创建Session
if(session != null){
session.removeAttribute("loginName");
session.invalidate();
}
logger.info("用户退出登录结束！");
return new CommonResult(ResultEnum.SUCCESS.getCode(), "退出成功！");
}