datatables 后台取到数据传到前台，排序的时候不请求后台，如何设置? 400 报错

datatables 后台取到数据传到前台，排序的时候不请求后台，如何设置? 400 报错 //使用ajax源
    "bServerSide": true,//页面在加载时就请求后台
    "bStateSave":true,
   "sAjaxSource":"/portal/applyListPortalPortletAction.action",
   "sServerMethod": "POST",
   "fnServerData": retrieveData,           //获取数据的处理函数 
       "aoColumnDefs": [
       { "bSortable": true, "targets": [ 0 ] },
       { "bSortable": true, "targets": [ 1 ] },
       { "bSortable": true, "targets": [ 2 ] },
       { "bSortable": true, "targets": [ 3 ] },
       {
           "targets": [4],
           "data": "portletId",
           "render": function(data, type, full) {
             return "<a + data + "'>修改</a>"+
               "  <a
           }
         }
       ]
    
     });