/// <summary>
        /// 通用请求方法
        /// </summary>
        /// <param name="url"></param>
        /// <param name="datas"></param>
        /// <param name="method">POST GET PUT DELETE</param>
        /// <param name="contentType">"POST application/x-www-form-urlencoded; charset=UTF-8"</param>
        /// <param name="encoding"></param>
        /// <returns></returns>
        public static string HttpRequest(string url, string data, string method = "PUT", string contentType = "application/json", Encoding encoding = null)
        {
            byte[] datas = System.Text.Encoding.GetEncoding("UTF-8").GetBytes(data);
            if (encoding == null)
                encoding = Encoding.UTF8;
            HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(url);
            request.Method = method;
            request.Timeout = 150000;
            request.AllowAutoRedirect = false;
            if (!string.IsNullOrEmpty(contentType))
            {
                request.ContentType = contentType;
            }
            if (url.StartsWith("https", StringComparison.OrdinalIgnoreCase))
            {
                ServicePointManager.ServerCertificateValidationCallback = new RemoteCertificateValidationCallback(CheckValidationResult);
            }
            Stream requestStream = null;
            string responseStr = null;
            try
            {
                if (datas != null)
                {
                    request.ContentLength = datas.Length;
                    requestStream = request.GetRequestStream();
                    requestStream.Write(datas, 0, datas.Length);
                    requestStream.Close();
                }
                else
                {
                    request.ContentLength = 0;
                }
                using (HttpWebResponse webResponse = (HttpWebResponse)request.GetResponse())
                {
                    Stream getStream = webResponse.GetResponseStream();
                    byte[] outBytes = ReadFully(getStream);
                    getStream.Close();
                    responseStr = Encoding.UTF8.GetString(outBytes);
                }
            }
            catch (Exception)
            {
                throw;
            }
            finally
            {
                request = null;
                requestStream = null;
            }
            return responseStr;
        }

private static bool CheckValidationResult(object sender, X509Certificate certificate, X509Chain chain, SslPolicyErrors errors)
        {
            return true; //总是接受  
        }

 public static byte[] ReadFully(Stream stream)
        {
            byte[] buffer = new byte[512];
            using (MemoryStream ms = new MemoryStream())
            {
                while (true)
                {
                    int read = stream.Read(buffer, 0, buffer.Length);
                    if (read <= 0)
                        return ms.ToArray();
                    ms.Write(buffer, 0, read);
                }
            }
        }