jquery AJAX 省市联动

JS //连动$(document).ready(function(){         doProvinceChangeJquery = function(oProvince, nCityId, sUrl){         var nPId = oProvince.options[oProvince.selectedIndex].value;           var requestMap = {      nPId: nPId      ,rnd:Math.random()*10000     };          jQuery.ajax( {                 type : 'POST',              url : sUrl,         data: requestMap,   dataType : 'json',         success : function(aArea) {                         var oCity=$("#"+nCityId);        for(var i = oCity.children().length - 1; i > 0; i --)    {          oCity.children("option[index='"+i+"']").remove();    }        for(var i = 0, nLen = aArea.length; i < nLen; i ++)    {     oCity.append("<option value='"+aArea[i].N_AREAID+"'>"+aArea[i].S_NAME+"</option>");    }                   },         error : function() {          alert("网路有异常，请稍候再试!")         }            });        }  });//jquery end  JAVA里面的 我用的SPRING MVC框架 /**  * 获取省市  * @param oRequest  * @param nPId  * @return List<Map>  */ @RequestMapping(value = "/subsys/ivrcs/module/commons/getArea.do", method = RequestMethod.POST) @ResponseBody public List<Map<String, Object>> getArea(HttpServletRequest oRequest,int nPId) {    List<Map<String, Object>> aArea = new ArrayList<Map<String, Object>>();  List<DynaBean> aTempArea = m_oCommonsService.getArea(nPId);  for (DynaBean oBean : aTempArea)  {   aArea.add(Tools.dynaBeanToMap(oBean));  }  return aArea; }