How to get the data from the querystring of jquery.form.js form submission

How to get the data from the querystring of jquery.form.js form submission

I am using jqury.form.js to submit a file along with some parameter.I also get the data in the alert in before send function,in this format filename=1&filename1=b&postedFile=.... this format.Now i want to get those data in the servlet individually.So now i m posting my code ..

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" " http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<head>
<title></title>
<script type="text/javascript">
    $(function() {            
      $('#fileUploadForm').ajaxForm({                 
        beforeSubmit: ShowRequest,
        success: SubmitSuccesful,
        error: AjaxError                               
      });                                    
    });            

    function ShowRequest(formData, jqForm, options) {
      var queryString = $.param(formData);
      alert('BeforeSend method: \n\nAbout to submit: \n\n' + queryString);
      return true;
    }

    function AjaxError() {
      alert("An AJAX error occured.");
    }

    function SubmitSuccesful(responseText, statusText) {        
      alert("SuccesMethod:\n\n" + responseText);
    }    
</script>
</head>
<body>
<form id="fileUploadForm" method="post" action="AccountDetails" enctype="multipart/form-data">
  <input type="text" name="filename" />
  <input type="text" name="filename1" />
  <input type="file" id="postedFile" name="postedFile" />
  <input type="submit" value="Submit" />
</form>
</body>
</html>

This is the jsp 
 and in the servlet end i am doing 

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String b= request.getParameter("filename");
System.out.println(b);
}
 i am getting null all the time .Please someone help