session过期，拦截ajax请求并跳转登录页面

1.方法一 ：1.1使用filter 和ajaxsetup 对ajax进行拦截并跳转登录页面

 public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
             throws IOException, ServletException {

         HttpServletResponse hresponse = (HttpServletResponse)response;
         HttpServletRequest hrequest = (HttpServletRequest)request;
         HttpServletResponseWrapper wrapper = new HttpServletResponseWrapper((HttpServletResponse) response);

         String logonStrings = config.getInitParameter("logonStrings");        // 登录登陆页面
         String redirectPath = hrequest.getContextPath() + config.getInitParameter("redirectPath");// 没有登陆转向页面
         String disabletestfilter = config.getInitParameter("disabletestfilter");// 过滤器是否有效
         String reString = hrequest.getRequestURI();
         if (disabletestfilter.toUpperCase().equals("Y")) {    // 过滤无效
             chain.doFilter(request, response);
             return;
         }
 //        User user = ( User ) hrequest.getSession().getAttribute("user");//判断用户是否登录
         String session_key = (String) hrequest.getSession().getAttribute("token");
         String username = (String) hrequest.getSession().getAttribute("username");
         if ("".equals(session_key) || session_key == null) {
             String[] logonList = logonStrings.split(",");
             if (this.isContains(reString, logonList)) {// 对登录页面不进行过滤
                 chain.doFilter(request, response);
                 return;
             }else{
                 request.setAttribute("username", null);
                 boolean isAjaxRequest = this.isAjaxRequest(hrequest);
                 if (isAjaxRequest) {
                     //系统的根url
                     chain.doFilter(request, response);
                     return;
                 }
                 wrapper.sendRedirect(redirectPath);
                 return;
             }
         }else {
             if(username !=null || username .equals("")) {
                 Pattern pattern = Pattern.compile("/iad/");
                 Matcher matcher = pattern.matcher(reString);
                 Pattern pattern1 = Pattern.compile("/iad/views/login/login.jsp");
                 Matcher matcher1 = pattern1.matcher(reString);
                 if(matcher.matches() ||matcher1.matches()){
                     wrapper.sendRedirect("/iad/views/home/index.jsp");
                     return;
                 }else {
                     chain.doFilter(request, response);
                     return;
                 }
             }else{
                 boolean isAjaxRequest = this.isAjaxRequest(hrequest);
                 if (isAjaxRequest) {
                     chain.doFilter(request, response);
                     return;
                 }
                 Pattern pattern = Pattern.compile(".*\\/views\\/login\\/login\\.jsp");
                 Matcher matcher = pattern.matcher(reString);
                 Pattern pattern2 = Pattern.compile(".*\\/oms/");
                 Matcher matcher2 = pattern2.matcher(reString);
                 // 是否是登陆页面
                 if (matcher.matches() || matcher2.matches()) {
                     request.setAttribute("username", username);
                     wrapper.sendRedirect("/iad/views/home/index.jsp");
                     return;
                 }
                 chain.doFilter(request, response);
                 return;
             }

         }

     }

判断是否为ajax

  public static boolean isAjaxRequest(HttpServletRequest request) {
         String header = request.getHeader("X-Requested-With");
         if (header != null && "XMLHttpRequest".equals(header))
             return true;
         else
             return false;
     }

1.2  全局js代码 可以抽取公共js 引入到你想要的页面

 $.ajaxSetup( {
         type: "POST" , // 默认使用POST方式
         headers: { // 默认添加请求头
             "Author": "CodePlayer" ,
             "Powered-By": "CodePlayer"
         } ,
         error: function(xhr, textStatus, errorMsg){ // 出错时默认的处理函数
           var sessionStatus = xhr.getResponseHeader('sessionstatus');
         if(sessionStatus == 'timeout') {
             var top = getTopWinow();
             var ids=layer.alert("导入成功！");
             window.location.href = "/iad/veiws/login/login.jsp";
         }

         }
     } );

总结： 这种方法的有个问题，就是ajax里面的error方法是一定走的， 提醒信息会出现两次

方法二：使用js定时器对前台的session进行查询（前提是你要将这个js放到公共页面）

  @ResponseBody
     @RequestMapping("/loginCheck")
     public Boolean loginCheck(HttpServletRequest request, HttpServletResponse response) {

         String session_key = (String) request.getSession().getAttribute("token");
         String username = (String) request.getSession().getAttribute("username");
         if (session_key == null || username == null) {
             response.setHeader("sessionstatus", "timeout");
             return false;
         }
         return true;
     }

 var timeid=window.setInterval("checkSession()", 1000);
             checkSession= function () {
                 $.ajax({
                     url: "../../loginCheck",
                     type: "POST",
                     dataType: "json",
                     success: function (result) {
                         if (result != true) {
                             window.clearInterval(timeid);
                             Ewin.alert({message: "由于您长时间没有操作, session已过期, 请重新登录"}).on(function (e) {
                                 window.location.href = "/iad/veiws/login/login.jsp";
                             })
                         }

                     }
                 });

             };

总结：这个方法可以将定义时间延长可以两秒查一次，确定是首先1.你的系统要有公共的页面，2.定时查询可能导致系统变慢