protected string GetJson(string url)

        {

            //访问https需加上这句话

           // ServicePointManager.ServerCertificateValidationCallback = new System.Net.Security.RemoteCertificateValidationCallback(CheckValidationResult);

            //访问http（不需要加上面那句话）

            WebClient wc = new WebClient();

            wc.Credentials = CredentialCache.DefaultCredentials;

            wc.Encoding = Encoding.UTF8;

            string returnText = wc.DownloadString(url);

            if (returnText.Contains("errcode"))

            {

                //可能发生错误

            }

            //Response.Write(returnText);

            return returnText;

        }

  /// <summary>

        /// 通过Post方式获取数据

        /// </summary>

        /// <param name="url"></param>

        /// <param name="data">可为空</param>

        /// <returns></returns>

 public string DoPost(string url, string data)

        {

            HttpWebRequest req = GetWebRequest(url, "POST");

            byte[] postData = Encoding.UTF8.GetBytes(data);

            Stream reqStream = req.GetRequestStream();

            reqStream.Write(postData, 0, postData.Length);

            reqStream.Close();

            HttpWebResponse rsp = (HttpWebResponse)req.GetResponse();

            Encoding encoding = Encoding.GetEncoding(rsp.CharacterSet);

            return GetResponseAsString(rsp, encoding);

        }

        public HttpWebRequest GetWebRequest(string url, string method)

        {

            HttpWebRequest req = (HttpWebRequest)WebRequest.Create(url);

            req.ServicePoint.Expect100Continue = false;

            req.ContentType = "application/x-www-form-urlencoded;charset=utf-8";

            req.ContentType = "text/json";

            req.Method = method;

            req.KeepAlive = true;

            req.UserAgent = "guanyisoft";

            req.Timeout = 1000000;

            req.Proxy = null;

            return req;

        }

        public string GetResponseAsString(HttpWebResponse rsp, Encoding encoding)

        {

            StringBuilder result = new StringBuilder();

            Stream stream = null;

            StreamReader reader = null;

            try

            {

                // 以字符流的方式读取HTTP响应

                stream = rsp.GetResponseStream();

                reader = new StreamReader(stream, encoding);

                // 每次读取不大于256个字符，并写入字符串

                char[] buffer = new char[256];

                int readBytes = 0;

                while ((readBytes = reader.Read(buffer, 0, buffer.Length)) > 0)

                {

                    result.Append(buffer, 0, readBytes);

                }

            }

            finally

            {

                // 释放资源

                if (reader != null) reader.Close();

                if (stream != null) stream.Close();

                if (rsp != null) rsp.Close();

            }

            return result.ToString();

        }