在一次項目中，在給客戶做系統時，需要調用客戶的系統獲取數據，客戶提供了獲取Token和獲取數據的接口，用戶名和密碼，認證方式是基于Bearer的，通過學習和找資料，提供一個C#示例

一個C#示例

1、傳入語句獲取數據

         /// <summary>
        /// 傳入語句獲取數據
        /// </summary>
        /// <param name="param"></param>
        /// <returns></returns>
        public async Task<string> ThirdSystemDataPostAsync(string param,string dataUrlAddress)
        {
            string token = await Bearer_TokenPostAsync();
            _logger.Warn($"獲取Token結構：{token}");
            string responseString = string.Empty;
            try
            {
                var tokenJson = JsonConvert.DeserializeObject<TokenResultDto>(token);
                _logger.Warn($"獲取Token值參數據：{tokenJson}");

                //跳過ssl驗證
                ServicePointManager.ServerCertificateValidationCallback = (sender, certificate, chain, sslPolicyErrors) => true;
                // 創建HttpWebRequest對象
                HttpWebRequest httpRequest = (HttpWebRequest)WebRequest.Create(dataUrlAddress);
                _logger.Warn($"入參數據：{param}");
                _logger.Warn($"智慧系統數據地址：{dataUrlAddress}");
                // 設置Post調??法
                httpRequest.Method = "Post";
                //設置參數傳輸類型
                httpRequest.ContentType = " application/json; charset=utf-8";
                // 設置Http Bearer認證的請求頭
                httpRequest.Headers.Add("Authorization", "Bearer " + tokenJson.accessToken);
                //傳輸參數格式轉換
                byte[] bytesRequestData = Encoding.UTF8.GetBytes(param);
                //_logger.Warn($"入參數據格式轉換：{bytesRequestData}");
                httpRequest.ContentLength = bytesRequestData.Length;
                Stream postStream = await httpRequest.GetRequestStreamAsync();
                postStream.Write(bytesRequestData, 0, bytesRequestData.Length);
                postStream.Close();
                //獲取設置身份認證及請求超時時間
                SetWebRequest(httpRequest);
                // HttpWebRequest發起調?
                using (HttpWebResponse myResponse = (HttpWebResponse)httpRequest.GetResponse())
                {
                    //myResponse.StatusCode
                    // StreamReader對象
                    StreamReader sr = new StreamReader(myResponse.GetResponseStream(), Encoding.UTF8);

                    // 返回結果
                    responseString = sr.ReadToEnd();

                    _logger.Warn($"調用智慧系統返回結果數據：{responseString}");
                    return responseString;
                }
            }
            catch (Exception ex)
            {
                //返回錯誤信息
                responseString = ex.ToString();
            }
            return responseString;

        }

2、獲取token

         /// <summary>
        /// 獲取token
        /// </summary>
        /// <returns></returns>
        private async Task<string> Bearer_TokenPostAsync(string sSoUrlAddress,string userName,string userPassword)
        {
            string responseString = string.Empty;
            try
            {
                // 創建HttpWebRequest對象
                HttpWebRequest httpRequest = (HttpWebRequest)WebRequest.Create(sSoUrlAddress);
                _logger.Warn($"智慧系統Token地址：{sSoUrlAddress}");
                // 設置Post調??法
                httpRequest.Method = "Post";
                //設置參數傳輸類型
                httpRequest.ContentType = " application/json; charset=utf-8";
                // 設置用戶名和密碼
                var usermesg = new UserMesgInput()
                {
                    Username = userName,
                    Password = userPassword,
                    UserDetail = true
                };
                string base64 = JsonConvert.SerializeObject(usermesg);
                //傳輸參數格式轉換
                byte[] bytesRequestData = Encoding.UTF8.GetBytes(base64);
                //_logger.Warn($"入參數據格式轉換：{bytesRequestData}");
                httpRequest.ContentLength = bytesRequestData.Length;

                Stream postStream = await httpRequest.GetRequestStreamAsync();
                postStream.Write(bytesRequestData, 0, bytesRequestData.Length);

                postStream.Close();
                //獲取設置身份認證及請求超時時間
                SetWebRequest(httpRequest);
                _logger.Warn($"獲取設置身份認證及請求超時時間");
                // HttpWebRequest發起調?
                using (HttpWebResponse myResponse = (HttpWebResponse)httpRequest.GetResponse())
                {
                    _logger.Warn($"StreamReader對象");
                    // StreamReader對象
                    StreamReader sr = new StreamReader(myResponse.GetResponseStream(), Encoding.UTF8);
                    //_logger.Warn($"返回結果{sr.ReadToEnd()}");
                    // 返回結果
                    responseString = sr.ReadToEnd();
                  
                    _logger.Warn($"調用智慧系統返回結果Token：{responseString}");
                    //return responseString;
                }
            }
            catch (Exception ex)
            {
                //返回錯誤信息
                responseString = ex.ToString();
            }
            return responseString;
        }

3、獲取設置身份認證及請求超時時間

        /// <summary>
        /// 獲取設置身份認證及請求超時時間
        /// </summary>
        /// <param name="request"></param>
        private static void SetWebRequest(HttpWebRequest request)
        {
            request.Credentials = CredentialCache.DefaultCredentials;
            request.Timeout = 1000000;

        }

4、在我使用的時候出現了下面的錯誤，通過查找是證書的問題，因為客戶的web訪問使用的IP地址訪問，所以在代碼中要加入跳過ssl驗證的一行代碼

System.Net.WebException: The SSL connection could not be established, see inner exception. The remote certificate is invalid according to the validation procedure.