HTTP请求

public static string DoPost(string url, IDictionary<string, string> parameters)
{
HttpWebRequest req = GetWebRequest(url, "POST");
req.ContentType = "application/x-www-form-urlencoded;charset=utf-8";

byte[] postData = Encoding.UTF8.GetBytes(BuildQuery(parameters));
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 static HttpWebRequest GetWebRequest(string url, string method)
{
HttpWebRequest req = (HttpWebRequest)WebRequest.Create(url);
req.ServicePoint.Expect100Continue = false;
req.Method = method;
req.KeepAlive = true;
req.UserAgent = "Top4Net";
req.Timeout = 1000 * 100;
return req;
}
/// <summary>
/// 把响应流转换为文本。
/// </summary>
/// <param name="rsp">响应流对象</param>
/// <param name="encoding">编码方式</param>
/// <returns>响应文本</returns>
public static string GetResponseAsString(HttpWebResponse rsp, Encoding encoding)
{
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);
return reader.ReadToEnd();
}
finally
{
// 释放资源
if (reader != null) reader.Close();
if (stream != null) stream.Close();
if (rsp != null) rsp.Close();
}
}

/// <summary>
/// 组装普通文本请求参数。
/// </summary>
/// <param name="parameters">Key-Value形式请求参数字典</param>
/// <returns>URL编码后的请求数据</returns>
public static string BuildQuery(IDictionary<string, string> parameters)
{
StringBuilder postData = new StringBuilder();
bool hasParam = false;

IEnumerator<KeyValuePair<string, string>> dem = parameters.GetEnumerator();
while (dem.MoveNext())
{
string name = dem.Current.Key;
string value = dem.Current.Value;
// 忽略参数名或参数值为空的参数
if (!string.IsNullOrEmpty(name) && !string.IsNullOrEmpty(value))
{
if (hasParam)
{
postData.Append("&");
}

postData.Append(name);
postData.Append("=");
postData.Append(Uri.EscapeDataString(value));
hasParam = true;
}
}
return postData.ToString();
}