Ext请求过程中jsonArray的使用方式

    /***
     * 取得用户组
     * 根据不同的用户组类型取得用户组
     * @param request request
     * @param response response
     */
    @RequestMapping(value = "/getUserGroup")
    public void getUserGroup(HttpServletRequest request,
            HttpServletResponse response)
    {
        setSysVersion(request);
        List<Map<String, Object>> list = null;
        String groupType = request.getParameter("groupType");
        String groupValue = request.getParameter("groupValue");
        if (groupType != null && groupValue != null)
        {
            list = applicationDao.getUserGroup(groupType,groupValue);
        }
        else if (groupType != null)
        {
            list = applicationDao.getUserGroup(groupType);
        }
        JSONArray jsonObj = JSONArray.fromObject(list);
        
        try
        {
            //向前台写数据
            response.getWriter().write(jsonObj.toString());
        }
        catch (IOException e)
        {
            logger.error("com.ecm.huawei.smartcare.subscriberAnalysis.getUserGroup"
                    + e);
        }
    }

Ext.Ajax.request(
							{
								url: userGroupUrl,
								params:{groupType:this.getType(),groupValue:inputValue},
								async : false,
								success: function(response) 
								{
									if(response.responseText == ""){
										isExist = false;
									}else if(Ext.util.JSON.decode(response.responseText)[0].SUBGROUP == inputValue){
										isExist = true;
									}else{
										isExist = false;	
									}
								}
					})