页面上异步接收数据形成select

js代码：document.getElementById("subcategory").options.length = 0;  $.getJSON("categoryList.do",function(data) {  $("<option value=''>--请选择--</option>").appendTo("#subcategory");  var i = 0;  $.each(data, function(i) {     $("<option value='" + data[i].id + "'>"+ data[i].name + "</option>").appendTo("#subcategory");  });});

catagoryList.do中的代码：

public String doExecute(ParameterParser paramParser, Context context,Navigator nav) {int pid = paramParser.getInt("pid");List<BackCategory> bl = backCategoryService.queryListByPid(pid);String bjson = JackSonUtil.getJson(bl);System.out.println(bjson);PrintWriter out = null;try {out = response.getWriter();} catch (IOException e) {e.printStackTrace();}if(out != null){out.print(bjson);out.flush();out.close();}return SUCCESS;}