easyui datagrid combobox通过url获取json数据的下拉框

------前台部分------------

<th align="left" width="12%" data-options="field:'relationtype',
formatter: function(value,row){
var dicname;
$.ajax(            //这是选中后返回的名称，没有这一步就会出现，选中离开后，还是原来的名称。
             {
               type: 'post',
               url: '${path }/tfieldTypeAction!getDICName.do',
               data: 'dicValue='+value,
               async:false, //必须，不然外部js无法获取内容
               dataType: 'text',
               success: function (result) {
                   dicname=result;
               },
               error: function (err) {
                   alert('error'+err);
                   return false;
               }
           });
           return dicname;
                               },
editor:{
type:'combobox',
options:{
valueField:'value',
textField:'name',
url:'${path }/tfieldTypeAction!getrelationtypeByMarkDCList.do',
editable:false,
required:true}
}">数据关联</th> 

------后台json部分-------

//json
public void getrelationtypeByMarkDCList()  
{
try {
HttpServletResponse response = ServletActionContext.getResponse();
response.setContentType("application/json");
response.setCharacterEncoding("UTF-8");
try {
creditRelationTypeList = wfDataDicImpl.getByMarkDCList(DictionaryID.RELATION_TYPE);
 jsonArray = JSONArray.fromObject( creditRelationTypeList );
} catch (Exception e) {
e.printStackTrace();
}
response.getWriter().write(jsonArray.toString());// 返回json类型对象
response.getWriter().close();
} catch (IOException e) {
e.printStackTrace();
}
       
}
/**
* 根据字段value查询name
*/
public void getDICName()
{
String dicname="";
HttpServletResponse response = ServletActionContext.getResponse();
response.setContentType("application/json");
response.setCharacterEncoding("UTF-8");
try {
if (!StringUtils.isEmptyOrNull(dicValue)) {
 
List<WfDataDic> wfdatadiclist = wfDataDicImpl
.getByMarkDCList(DictionaryID.RELATION_TYPE);
for (WfDataDic wfDataDic : wfdatadiclist) {
if (dicValue.equals(wfDataDic.getValue())) {
 dicname=wfDataDic.getName();
}
}
response.getWriter().write(dicname);
response.getWriter().close();
}
} catch (IOException e) {
e.printStackTrace();
}catch (Exception e) {
e.printStackTrace();
}
 
}

--------获取节点部分-------

if(!StringUtils.isEmptyOrNull(lc.getRelationtype()))
 {
 sb.append("\"relationtype\":\""+lc.getRelationtype()).append("\",");
/*for (WfDataDic wfDataDic : wdclist) {
if(lc.getRelationtype().equals(wfDataDic.getValue()))
{
sb.append("\"name\":\""+wfDataDic.getName()).append("\",");
}
 }*/
 }