Ajax上传file出现的bad request问题

var formData = new FormData($("#form")[0]);
               $.ajax({
                   url:‘${pageContext.request.contextpath}/manage/matrix/add‘,type:‘post‘,data:formData,async : false,cache : false,contentType : false,processData : false,success:function(data){
                       myAlert(data.message,function(){
                           window.location.href="${pageContext.request.contextpath}/manage/matrix/list";
                       });
                   },error:function(){
                       myAlert("网络错误",function(){
                               window.location.href="${pageContext.request.contextpath}/manage/matrix/list";
                       });
                   }
               });