/// <summary>

        ///友商网检查用户登录接口

        /// </summary>

        /// <param name="userAccount"></param>

        /// <returns></returns>

        public bool Exists(string userAccount)

        {

            try

            {

                string url = "http://agent.youshang.com/federation/commonservice/servicePortal.do"; //友商网接口

                string urlParam = "partnerId={0}&cipherCode={1}&iv={2}"; //接口的URL参数

                string iv = AES_Crypto.GetIv(16); //生成iv代码

                string xmlLogin = this.getLoginXML(userAccount); //TUser对象转换为xml文件

                //AES加密用户XML数据

                string cipherCode = AES_Crypto.AESEncrypt(xmlLogin, _aesKey, iv);

                cipherCode = HttpUtility.UrlEncode(cipherCode);//HTML ENCODE

                iv = HttpUtility.UrlEncode(iv);//HTML ENCODE

                urlParam = string.Format(urlParam, _partnerID, cipherCode, iv);

                string response = this.HttpPost(url, urlParam); //提交数据....   

                return response.Trim().Length > 0;

            }

            catch //如友商网不存在该用户，会抛出服务器内部错误

            {

                //在这里接收到异常视该用户不存在

                return false;

            }

        }