使用HttpWebRequest方式访问外部接口

第一步，如果不是http网站，则需认证信托证书

        /// <summary>
        /// 认证信托证书
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="cert"></param>
        /// <param name="chain"></param>
        /// <param name="error"></param>
        /// <returns></returns>
        public static bool RemoteCertificateValidate(object sender, X509Certificate cert, X509Chain chain, SslPolicyErrors error)
        {
            LogHelper.WriteInfo("Warning, trust any certificate");
            return true;
        }

第二步，文字中文信息转成UTF-8格式

　　　　　/// <summary>
        /// 把中文转换成UTF-8 
        /// </summary>
        /// <param name="str"></param>
        /// <returns></returns>
        public static string UrlEncode(string str)
        {
            byte[] utf8 = Encoding.UTF8.GetBytes(str);
            string s = "";
            foreach (byte b in utf8)
            {
                s += string.Format("%{0:X2}", b);
            }
            return s;
        }

第三步，使用HttpRequest方式访问指定Url

　　　　 /// <summary>
        /// 使用HttpRequest方式访问Url
        /// </summary>
        /// <param name="url"></param>
        /// <returns></returns>
        public static string CreateHttpRequest(string url)
        {
            try
            {
                //创建HttpWebRequest请求连接
                HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(url);
                //获取HttpResponse响应
                HttpWebResponse response = (HttpWebResponse)request.GetResponse();
                Stream stream = null;
                StreamReader reader = null;
                string strLine = string.Empty;
                string strResponse = string.Empty;
                //判断请求是否正常
                if (response.StatusCode == HttpStatusCode.OK)
                {
                    stream = response.GetResponseStream();
                    reader = new StreamReader(stream, Encoding.UTF8);
                    //逐行读取
                    while ((strLine = reader.ReadLine()) != null)
                    {
                        strResponse += strLine + "\r\n";
                    }
                }
            }
            catch (Exception e)
            {
                LogHelper.WriteError(e.Message, e);
            }
            return strResponse;
        }