Jquery跨域调用struts2的Action返回json数据易出现的问题

必须有jsoncallback

1.

$.getJSON("/queryName.action?jsoncallback=?",function(json){

                 alert("json="+json);

                 console.log(json);

            });

2.

           <actionname="queryName"method="queryName"class="testAction">

                <resultname="success"type="json">

                     <paramname="callbackParameter">jsoncallback</param>

                </result> 

           </action>

3.

try{

                userList=userService.queryInfoByUserId(userId);

                if(!CollectionUtils.isEmpty(userPostList)){

                     code =userList.get(0).getCode();

                     name =userList.get(0).getName();

                }

              

                Map<String,Object> map =newHashMap<String, Object>();

                map.put("name", name);

                map.put("id", code);

                JSONArrayarr=JSONArray.fromObject(map);

                String  callback =jsoncallback;

             String jsoncallback = callback+"({'result':"+arr+"})";

             JsonFormatUtil.returnJsonResponse(jsoncallback);

           }catch(Exception e) {

                JsonFormatUtil.returnErrorMsgInfoResponse(e.getMessage());

                e.printStackTrace();

           }

           

           return null;