Redirect on Ajax Jquery Call

Question

I am newbie to ajax here and I know somebody would have encountered this problem already. I have a legacy app built on Spring MVC, it has a interceptor(filter) that redirects the user to the login page whenever there is no session.

public class SessionCheckerInterceptor extends HandlerInterceptorAdapter {
 public boolean preHandle(HttpServletRequest request,
   HttpServletResponse response, Object handler) throws Exception {
  HttpSession session = request.getSession();

  // check if userInfo exist in session
  User user = (User) session.getAttribute("user");
  if (user == null) {
   response.sendRedirect("login.htm");
   return false;
  }
  return true;
 }
}

For non-xmlhttp request, this works fine.. but when I try to use ajax in my application, everything gets weird, it is not able to redirect to the login page correctly. As check the value of the

xhr.status = 200 textStatus = parseError errorThrown = "Invalid JSON -Markup of my HTML Login Page-

$(document).ready(function(){
        jQuery.ajax({
            type: "GET",
            url: "populateData.htm",
            dataType:"json",
            data:"userId=SampleUser",
            success:function(response){
             //code here
            },
         error: function(xhr, textStatus, errorThrown) {
                alert('Error!  Status = ' + xhr.status);
             }

        });
});

我检查了我的firebug,有一个302 HTTP响应,但我不知道如何捕获响应并将用户重定向到登录页面.这有什么想法吗？谢谢.

Answer 1

JQuery正在寻找一个json类型的结果,但由于重定向是自动处理的,它将接收生成的login.htm页面的html源代码.

一个想法是让浏览器知道它应该通过向redirect结果对象添加变量并在JQuery中检查它来重定向:

$(document).ready(function(){ 
    jQuery.ajax({ 
        type: "GET", 
        url: "populateData.htm", 
        dataType:"json", 
        data:"userId=SampleUser", 
        success:function(response){ 
            if (response.redirect) {
                window.location.href = response.redirect;
            }
            else {
                // Process the expected results...
            }
        }, 
     error: function(xhr, textStatus, errorThrown) { 
            alert('Error!  Status = ' + xhr.status); 
         } 

    }); 
}); 

您还可以在响应中添加标头变量,并让浏览器决定重定向的位置.在Java中,不是重定向,而是response.setHeader("REQUIRES_AUTH", "1")在JQuery中执行成功(!):

//....
        success:function(response){ 
            if (response.getResponseHeader('REQUIRES_AUTH') === '1'){ 
                window.location.href = 'login.htm'; 
            }
            else {
                // Process the expected results...
            }
        }
//....

希望有所帮助.

我的答案深受这个帖子的启发,如果你还有一些问题,不应该留下任何问题.