C# 提交网页请求时出现如下错误: System.Net.WebException: 操作超时

原因一：

连接超时时间 Timeout 以及写入Post数据超时时间 ReadWriteTimeout 设置得太短，一般要设置大于6000ms。

 

原因二：

Expect100Continue 属性的值设置为了true，将 Expect100Continue 属性的值设置为 false 即可解决问题。

 

 

代码：

public static string Post(string xml, string url, bool isUseCert, int timeout)
{
System.GC.Collect();//垃圾回收，回收没有正常关闭的http连接

string result = "";//返回结果

HttpWebRequest request = null;
HttpWebResponse response = null;
Stream reqStream = null;

try
{
//设置最大连接数
ServicePointManager.DefaultConnectionLimit = 200;
//设置https验证方式
if (url.StartsWith("https", StringComparison.OrdinalIgnoreCase))
{
ServicePointManager.ServerCertificateValidationCallback =
new RemoteCertificateValidationCallback(CheckValidationResult);
}

/***************************************************************
* 下面设置HttpWebRequest的相关属性
* ************************************************************/
request = (HttpWebRequest)WebRequest.Create(url);

request.Method = "POST";
request.Timeout = timeout * 1000;

//设置代理服务器
//WebProxy proxy = new WebProxy(); //定义一个网关对象
//proxy.Address = new Uri(WxPayConfig.PROXY_URL); //网关服务器端口:端口
//request.Proxy = proxy;

//设置POST的数据类型和长度
request.ContentType = "text/xml";
byte[] data = System.Text.Encoding.UTF8.GetBytes(xml);
request.ContentLength = data.Length;

//这个在Post的时候，一定要加上，如果服务器返回错误，他还会继续再去请求，不会使用之前的错误数据，做返回数据
request.ServicePoint.Expect100Continue = false;

//是否使用证书
if (isUseCert)
{
string path = HttpContext.Current.Request.PhysicalApplicationPath;
X509Certificate2 cert = new X509Certificate2(path + WxPayConfig.SSLCERT_PATH, WxPayConfig.SSLCERT_PASSWORD);
request.ClientCertificates.Add(cert);
Log.Debug("WxPayApi", "PostXml used cert");
}

//往服务器写入数据
reqStream = request.GetRequestStream();
reqStream.Write(data, 0, data.Length);
reqStream.Close();

//获取服务端返回
response = (HttpWebResponse)request.GetResponse();

//获取服务端返回数据
StreamReader sr = new StreamReader(response.GetResponseStream(), Encoding.UTF8);
result = sr.ReadToEnd().Trim();
sr.Close();
}
catch (System.Threading.ThreadAbortException e)
{
Log.Error("HttpService", "Thread - caught ThreadAbortException - resetting.");
Log.Error("Exception message: {0}", e.Message);
System.Threading.Thread.ResetAbort();
}
catch (WebException e)
{
Log.Error("HttpService", e.ToString());
if (e.Status == WebExceptionStatus.ProtocolError)
{
Log.Error("HttpService", "StatusCode : " + ((HttpWebResponse)e.Response).StatusCode);
Log.Error("HttpService", "StatusDescription : " + ((HttpWebResponse)e.Response).StatusDescription);
}
throw new WxPayException(e.ToString());
}
catch (Exception e)
{
Log.Error("HttpService", e.ToString());
throw new WxPayException(e.ToString());
}
finally
{
//关闭连接和流
if (response != null)
{
response.Close();
}
if(request != null)
{
request.Abort();
}
}
return result;
}