ajax接收后端传回的jsonarray数据，追加到<select>

import net.sf.json.JSONArray;

@RequestMapping(value = "admin/selectLearnPackge/{trainingId}", method = RequestMethod.POST)
    public void selectLearnPackge(HttpServletResponse response,@PathVariable int trainingId) throws IOException {
        List<LearnPackage> learnPackageList = learnPackageService.getLearnPackageList(trainingId);
        JSONArray jsonArray = JSONArray.fromObject(learnPackageList);
        response.setContentType("text/html;charset=utf-8");
        response.getWriter().println(jsonArray);
    }

　　

function selectLearnPackge() {
            var trainingId = $("#trainingId").val();
            $.ajax({
                url : "admin/selectLearnPackge/"+trainingId,
                async : true,
                type : "POST",
                dataType : "json",
                // 成功后开启模态框
                success:function(result) {
                    $("#learnPackageId").empty();
                    $("#learnPackageId").append("<option value=''>请选择</option>");
                    $.each(result, function (i, item) {
                        $("#learnPackageId").append("<option value="+item.id+">"+item.packageName+"</option>");
                    });
                },
                error : function() {
                    alert("请求失败");
                }
            });
        }

　　

　　　　　　　　　　　　　　　　　　
                            <select id="trainingId" style="margin-left: 20px;width: 150px;" name="trainingId" onchange="selectLearnPackge()">
                                <option value="">请选择...</option>
                                <c:forEach items="${trainingList}" var="li">
                                    <option value="${li.trainingId}">${li.trainingName}</option>
                                </c:forEach>
                            </select>
                          
                            <select id="learnPackageId" style="margin-left: 20px;width: 150px;" name="learnPackageId">
                                <option value="">请选择...</option>
                            </select>