根据URL请求数据

   /// <summary>
        /// HTTP POST方式请求数据
        /// </summary>
        /// <param name="url">URL.</param>
        /// <param name="param">POST的数据</param>
        /// <returns></returns>
        public static string HttpPost(string url, string param)
        {
            HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(url);
            request.Method = "POST";
            request.ContentType = "application/x-www-form-urlencoded";
            request.Accept = "*/*";
            request.Timeout = 15000;
            request.AllowAutoRedirect = false;

            StreamWriter requestStream = null;
            WebResponse response = null;
            string responseStr = null;

            try
            {
                requestStream = new StreamWriter(request.GetRequestStream());
                requestStream.Write(param);
                requestStream.Close();

                response = request.GetResponse();
                if (response != null)
                {
                    StreamReader reader = new StreamReader(response.GetResponseStream(), Encoding.UTF8);
                    responseStr = reader.ReadToEnd();
                    reader.Close();
                }
            }
            catch (Exception)
            {
                throw;
            }
            finally
            {
                request = null;
                requestStream = null;
                response = null;
            }

            return responseStr;
        }

        /// <summary>
        /// HTTP GET方式请求数据.
        /// </summary>
        /// <param name="url">URL.</param>
        /// <returns></returns>
        public static string HttpGet(string url)
        {
            HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(url);
            request.Method = "GET";
            //request.ContentType = "application/x-www-form-urlencoded";
            request.Accept = "*/*";
            request.Timeout = 15000;
            request.AllowAutoRedirect = false;

            WebResponse response = null;
            string responseStr = null;

            try
            {
                response = request.GetResponse();

                if (response != null)
                {
                    StreamReader reader = new StreamReader(response.GetResponseStream(), Encoding.UTF8);
                    responseStr = reader.ReadToEnd();
                    reader.Close();
                }
            }
            catch (Exception)
            {
                throw;
            }
            finally
            {
                request = null;
                response = null;
            }

            return responseStr;
        }