使用easyui从servlet传递json数据到前端页面的两种方法

//重写doGet方法
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
 // TODO Auto-generated method stub
​
 request.setCharacterEncoding("UTF-8");//防止request请求时中文数据出现乱码
 String flag = request.getParameter("flag");//通过flag值判定增删改查操作
 if(flag == null) {
 queryOffer(request,response);
 }else if("add".equals(flag)){
 addOffer(request,response);
 }else if("del".equals(flag)) {
 deleteOffer(request,response);
 }else if("update".equals(flag)) {
 updateOffer(request,response);
 }
}
​
//处理从数据库查询到的数据以返回前端
protected void queryOffer(HttpServletRequest request, HttpServletResponse response) {
 // TODO Auto-generated method stub
 List<Offer> offers = new ArrayList<Offer>();
 offers = offerservice.queryOfferService();
 try {
 String str=JSONArray.toJSONString(offers);//将数据库查询到的集合转换成JSON字符串
 System.out.println(str);
 response.setContentType("text/html;charset=utf-8");//防止response时中文数据乱码
 response.getWriter().print(str);//向前台传递字符串
 } catch (Exception e) {
 // TODO Auto-generated catch block
 e.printStackTrace();
 }
}

<table id="dg" title="用户列表" class="easyui-datagrid" style="width:80%;height:250px"
 url="<%=request.getContextPath() %>/OfferServlet" 
 toolbar="#toolbar"
 rownumbers="true" fitColumns="true" singleSelect="true">
 <thead>
 <tr>
 <th field="offerid" width="50">商品ID</th>
 <th field="offername" width="100">商品名称</th>
 <th field="offertype" width="200">商品类型</th>
 <th field="offerdesc" width="200">商品描述</th>
 <th field="price" width="200">商品价格</th>
 </tr>
 </thead>
 </table>

<table id="dg" title="用户列表" class="easyui-datagrid" style="width:1000px;height:250px" toolbar="#toolbar">
</table>

$(function(){
 $('#dg').datagrid({
 url:"${pageContext.request.contextPath}/OfferServlet",//servlet路径
 columns:[[
 {field:'offerid',title:'商品ID',width:100},
 {field:'offername',title:'商品名称',width:100},
 {field:'offertype',title:'商品类型',width:100},
 {field:'offerdesc',title:'商品描述',width:300},
 {field:'price',title:'商品价格',width:150}
 ]] 
 });
});