1.将get获取的数据,UrlDecode后返回

public static string SendGet(string url)
{
  HttpWebRequest httpWebRequest = (HttpWebRequest)HttpWebRequest.Create(url);
  httpWebRequest.Method = "GET";
  HttpWebResponse httpWebResponse = httpWebRequest.GetResponse() as HttpWebResponse;
  Stream stream = httpWebResponse.GetResponseStream();
  StreamReader streamReader = new StreamReader(stream, Encoding.UTF8);
  string strOut = streamReader.ReadToEnd();
  httpWebResponse.Close();
  strOut = HttpUtility.UrlDecode(strOut);
  return strOut;
}

2.post请求,StreamReader方法获取ResponseStream中的信息

public static string SendPost(string data, string url, string contentType)
{
  string content = string.Empty;
  HttpWebRequest httpWebRequest = WebRequest.Create(url) as HttpWebRequest;
  httpWebRequest.AllowAutoRedirect = true;
  httpWebRequest.Method = "POST";
  httpWebRequest.ContentType = contentType;
  using (StreamWriter sw = new StreamWriter(httpWebRequest.GetRequestStream()))
  {
    sw.Write(data);
  }
  HttpWebResponse httpWebResponse = httpWebRequest.GetResponse() as HttpWebResponse;
  using (StreamReader sr = new StreamReader(httpWebResponse.GetResponseStream()))
  {
    content = sr.ReadToEnd();
  }
  return content;
}

3.post请求,通过Stream.Read方法获取ResponseStream中的信息

 public static String RequestUrl(String url, byte[] data, String method = "POST")
 {
     try
     { 
       WebRequest request = WebRequest.Create(url);
        request.Method = method;
        request.ContentType = "application/x-www-form-urlencoded"; 
        if (data != null && data.Length > 0)
        {
            request.ContentLength = data.Length;
            Stream newStream = request.GetRequestStream();
            newStream.Write(data, 0, data.Length);
            newStream.Close();
        }
        else
        {
            request.ContentLength = 0;
        }
        WebResponse response = request.GetResponse();
        Stream stream = response.GetResponseStream();
        MemoryStream ms = new MemoryStream();
        long ChunkSize = 1024;
        byte[] buffer = new byte[ChunkSize];
        long dataLengthToRead = response.ContentLength;//获取响应数据的总大小
        while (dataLengthToRead > 0)
        {
            int lengthRead = stream.Read(buffer, 0, Convert.ToInt32(ChunkSize));//读取的大小
            ms.Write(buffer, 0, lengthRead);
            dataLengthToRead = dataLengthToRead - lengthRead;
        }
        stream.Close();
        response.Close(); 
        string responseText = Encoding.UTF8.GetString(ms.ToArray());
        return responseText; 
    }
    catch (Exception ex)
    {
        return ex.Message;
    }
}