C#Post方法GetResponse抛出异常获取不到返回

先描述一下问题产生，对接某公司程序时，由于返回请求错误，对方服务器返回400,415，等错误，然而这种异常内包含某些对方返回的信息，普通的如果post方法内未进行Response的异常处理，那么恭喜你，你悲剧了，获取到的信息就是这些“Exception:远程服务器返回错误: (500) 内部服务器错误”。然而这并不是我们想要的，那么就需要对这种情况进行处理了。（在此记录一下，方便日后查看）下面先看一个post：

  public string PostHtml(string url, string args){return PostHtml(url, args, _webEncoding);}public string PostHtml(string url, string args, WebProxy proxy){return PostHtml(url, args, _webEncoding, proxy);}public string PostHtml(string url, string args, Encoding enc, WebProxy proxy = null){string result = null;try{//enc = Encoding.UTF8;var bytes = Encoding.UTF8.GetBytes(args);ServicePointManager.ServerCertificateValidationCallback = CheckValidationResult;var request = (HttpWebRequest)WebRequest.Create(url);request.CookieContainer = _webCookieContainer;request.Timeout = _timeout;request.ReadWriteTimeout = _timeout;request.UserAgent = _userAgent;request.Referer = _referer;request.ContentType = _contentType; //;//_contentTyperequest.Headers.Add("Cache-control: no-cache");request.Headers.Add("Accept-Language: zh-cn");request.Accept = "application/json";request.ContentLength = bytes.Length;request.Method = "POST";request.ProtocolVersion = HttpVersion.Version11;if (proxy != null) request.Proxy = proxy;using (var stream = request.GetRequestStream()){stream.Write(bytes, 0, bytes.Length);}request.ServicePoint.Address.ToString();var response = (HttpWebResponse)request.GetResponse();if (response.Cookies != null) _webCookieContainer.Add(response.Cookies);var recvStream =response.GetResponseStream();//response.CharacterSet = Encoding.GetEncoding("UTF-8");if (recvStream != null){if (response.ContentEncoding.ToLower().Contains("gzip")){using (GZipStream stream = new GZipStream(recvStream, CompressionMode.Decompress)){using (StreamReader reader = new StreamReader(stream, Encoding.GetEncoding("UTF-8"))){result = reader.ReadToEnd();}}}else if (response.ContentEncoding.ToLower().Contains("deflate")){using (DeflateStream stream = new DeflateStream(recvStream, CompressionMode.Decompress)){using (StreamReader reader = new StreamReader(stream, Encoding.GetEncoding("UTF-8"))){result = reader.ReadToEnd();}}}else{using (StreamReader reader = new StreamReader(recvStream, Encoding.GetEncoding("UTF-8"))){result = reader.ReadToEnd();}}}_lastUrl = response.ResponseUri.ToString();response.Close();request.Abort();}catch (Exception ex){result = $"Exception:{ex.Message}";}return result;}

异常直接return result，然而result中没有任何有用信息。那就抛出异常处理一下看下一个post：

 public string PianYunHttpPost(string Url, Dictionary<string, string> parms){StringBuilder sb = new StringBuilder();foreach (var item in parms){if (sb.Length != 0)sb.Append("&");sb.Append(HttpUtility.UrlEncode(item.Key) + '=' + HttpUtility.UrlEncode(item.Value));}byte[] dataArray = Encoding.UTF8.GetBytes(sb.ToString());// Console.Write(Encoding.UTF8.GetString(dataArray));HttpWebRequest request = (HttpWebRequest)WebRequest.Create(Url);request.Timeout = 5000;request.ReadWriteTimeout = 5000;request.Method = "POST";request.ContentType = "application/x-www-form-urlencoded";request.ContentLength = dataArray.Length;//request.CookieContainer = cookie;try{Stream dataStream = request.GetRequestStream();dataStream.Write(dataArray, 0, dataArray.Length);dataStream.Close();HttpWebResponse response = (HttpWebResponse)request.GetResponse();StreamReader reader = new StreamReader(response.GetResponseStream(), Encoding.UTF8);String res = reader.ReadToEnd();reader.Close();//Console.Write("\nResponse Content:\n" + res + "\n");return res;}catch (WebException e){using (WebResponse response = e.Response){HttpWebResponse httpResponse = (HttpWebResponse)response;//Console.WriteLine(e);if (response == null){return  e.ToString();}using (Stream data = response.GetResponseStream())using (var reader = new StreamReader(data)){string text = reader.ReadToEnd();// Console.WriteLine(text);return text;}}}}

多出的地方就是catch webException然而就是这个东西吧自身需要的东西给反回来了，问题就是这样。下面这个是post解决乱码的问题，具体的编码方式自己搞下吧：

 public string HttpPostData(String url, String data){string strReturn = string.Empty;byte[] byteData = Encoding.UTF8.GetBytes(data);  //在转换字节时指定编码格式HttpWebRequest req = (HttpWebRequest)HttpWebRequest.Create(url);req.Method = "POST";req.ContentType = "application/x-www-form-urlencoded";req.ContentLength = byteData.Length;try{using (Stream reqStream = req.GetRequestStream()){reqStream.Write(byteData, 0, byteData.Length);//发送数据}//get reponse data and parseusing (WebResponse response = req.GetResponse()){//解决乱码：utf-8 + streamreader.readtoendStreamReader reader = new StreamReader(response.GetResponseStream(), Encoding.GetEncoding("utf-8"));strReturn = reader.ReadToEnd();reader.Close();reader.Dispose();}}catch (Exception ex){throw ex;}return strReturn;}