C# Post方式传输报文，和处理响应

public string DoPost(string url, string data)
{
HttpWebRequest req = GetWebRequest(url, "POST");
byte[] postData = Encoding.UTF8.GetBytes(data);
Stream reqStream = req.GetRequestStream();
reqStream.Write(postData, 0, postData.Length);
reqStream.Close();
HttpWebResponse rsp = (HttpWebResponse)req.GetResponse();
Encoding encoding = Encoding.GetEncoding(rsp.CharacterSet);
return GetResponseAsString(rsp, encoding);
}

public HttpWebRequest GetWebRequest(string url, string method)
{
HttpWebRequest req = (HttpWebRequest)WebRequest.Create(url);
req.ServicePoint.Expect100Continue = false;
req.ContentType = "application/x-www-form-urlencoded;charset=utf-8";
req.ContentType = "text/json";
req.Method = method;
req.KeepAlive = true;
req.UserAgent = "mysoft";
req.Timeout = 1000000;
req.Proxy = null;
return req;
}

public string GetResponseAsString(HttpWebResponse rsp, Encoding encoding)
{
StringBuilder result = new StringBuilder();
Stream stream = null;
StreamReader reader = null;
try
{
// 以字符流的方式读取HTTP响应
stream = rsp.GetResponseStream();
reader = new StreamReader(stream, encoding);
// 每次读取不大于256个字符，并写入字符串
char[] buffer = new char[256];
int readBytes = 0;
while ((readBytes = reader.Read(buffer, 0, buffer.Length)) > 0)
{
result.Append(buffer, 0, readBytes);
}
}
finally
{
// 释放资源
if (reader != null) reader.Close();
if (stream != null) stream.Close();
if (rsp != null) rsp.Close();
}

return result.ToString();
}