Java过滤器应用-对Ajax请求做Session失效判断

过滤器常用来对Session过期做判断

Layout.js　　

1.为ajax请求添加标识　　　

2.无论ajax请求成功与否，complete函数终会执行

 // 全局Ajax设置, 用于session过期后的跳转
 function ajaxSetup() {
     $.ajaxSetup({
         timeout : 10000,
         beforeSend : function(xhr) {
             //添加ajax请求标识
             xhr.setRequestHeader("ajaxReq", "ajax");
         },
         complete : function(xhr, ts) {
             if (xhr.statusText == 'sessiontimeout' && xhr.status == 403) {
                 // 跳转
                 window.location.href = "login.jsp";
             }
         }
     });
 }

请求过滤器，Session过期则修改请求状态为403（或其他），设置过期标识sessionState为timeout，便于ajax回调函数判断。

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

         HttpServletRequest req = (HttpServletRequest) request;
         HttpServletResponse res = (HttpServletResponse) response;
         String servletPath = req.getServletPath();

         if(except.contains(req.getRequestURI())){
             chain.doFilter(request, response);
         }

         Object sessionObj = req.getSession().getAttribute(key);
         if(sessionObj==null){
             //如果是ajax请求
             if(req.getHeader("ajaxReq")!=null && req.getHeader("ajaxReq").equals("ajax")){
                 res.setHeader("sessionState", "timeout");
                 res.setStatus(403);
                 return;
             }else{
                 chain.doFilter(request, response);
                 String contextPath = req.getContextPath();
                 String redirect = servletPath + "?" + StringUtils.defaultString(req.getQueryString());
                 res.sendRedirect(contextPath + forward + "?redirect=" + URLEncoder.encode(redirect, "UTF-8"));
             }

         }else{
             // pass the request along the filter chain
             chain.doFilter(request, response);
             System.out.println("chain.do after");
         }

     }

目前发现ajax全局设置对load函数无效。