ajax返回json的简单运用

function pop(){
  $.ligerDialog.prompt('添加环保知识分类', function (yes,value) {
    if(yes){
loreClass(value);
}
  });
}
function loreClass(category){
  $.ajax({
     type:"post",
     url:"<%=basePath%>Hb_classifyServlet",
     data:"b=save&category="+encodeURIComponent(category),
     dataType:"json",
     success:function(data){
var dataObj = eval(data) ;
var select = $("#selectID");
select.empty();
         $("#selectID").append("<option value='' >请选择</option>") ;
for(var i=0;i<dataObj.length;i++){
//alert(dataObj[i].category+"====="+dataObj[i].contentId);
             $("#selectID").append("<option value='"+dataObj[i].contentId+"'>"+dataObj[i].category+"</option>");
}
alert("添加分类成功!!") ;
     }
  }) ;
}

Servlet代码

import net.sf.json.JSONArray;
protected void saveClass(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
         String category = request.getParameter("category");
Hb_classify hc = new Hb_classify() ;
hc.setCategory(category);
Hb_classifyDao dao = new Hb_classifyDao(youngdb) ;
dao.save(hc);
List<Hb_classify> list = dao.findAll(0);
JSONArray json =JSONArray.fromObject(list);
response.getWriter().print(json.toString()) ;
}