jQuery中ajax应用json数据类型总是跳过success执行error语句

    $.ajax({
            type : "post",
            dataType:"json",
            async: true,
            url : "adddata_action.jsp",
            data : paras,
            success: function(data) {
                if(data.response=='success')
                {
                    alert(data.message);
                    $("#arrange_sheet").dialog("close");
                }else{
                    alert(data.message);
                }
                
            },
            error : function(XMLHttpRequest, textStatus, errorThrown) {
                alert("error");
                /*
                $("#dialog-message_failed").dialog("open");
                */
            }