public HttpResponseMessage GetAllEmployee()
        {
            // 数据库中找到所有employee的信息
            // 如果工资为-1
            // 则不显示
            // 序列化成Json
            ArrayList list = ManagementHelper.GetAllEmployee();

            HttpResponseMessage response = new HttpResponseMessage();

            if (list.Count == 0)
            {
                response.Content    = new StringContent("查找失败");
                response.StatusCode = HttpStatusCode.NotFound;
            }
            else
            {
                response.Content = new StringContent(JsonObjectConverter.ObjectToJson(list));

                response.StatusCode = HttpStatusCode.OK;
            }

            return(response);
        }