后台：

//得到报修人数据
public String getBaoxiuInfo(){
	HttpServletRequest request = getHttpServletRequest();
	WarrantyService workorder = new WarrantyService();
	String ws_num = request.getParameter("re_num");
	workorder.setWs_num(ws_num);   //设置编号
	     JSONArray jsonArray = new JSONArray();
	     JSONObject jsonData = new JSONObject();
	     jsonArray.add(JsonUtil.beanToJson(getiWarrantyServiceService().selectBaoxiuInfo(workorder))); //将得到的model类转为Json，放入json数组中
	     jsonData.put("BaoxiuInfo",jsonArray);     //jsonData中数据格式：{"BaoxiuInfo": [{"ws_num":"abcd"}]}
	     printHttpServletResponse(jsonData.toString());
	     
		return null;
	}

前台：

	Ext.Ajax.request({
		url: 'warrantyServiceAction!getBaoxiuInfo.shtml',method: 'POST',params: {re_num:recordtoedit.get("re_num")},success: function(response) {
		var jsonObj = Ext.util.JSON.decode(response.responseText);
												
		alert(jsonObj.BaoxiuInfo[0].ws_num);  //结果为abcd
												
												
		}
	});