1、不带参数的POST请求

public static string Post(string url)
{  string result = "";  HttpWebRequest req = (HttpWebRequest)WebRequest.Create(url);  req.Method = "POST";  HttpWebResponse resp = (HttpWebResponse)req.GetResponse();  Stream stream = resp.GetResponseStream();  //获取内容  using (StreamReader reader = new StreamReader(stream, Encoding.UTF8))  {  result = reader.ReadToEnd();  }  return result;
}  

2、带参数的POST请求

public static string Post(string url,Dictionary<string,string> dic)
{  string result = "";  HttpWebRequest req = (HttpWebRequest)WebRequest.Create(url);  req.Method = "POST";  req.ContentType = "application/x-www-form-urlencoded";  #region 添加Post 参数  StringBuilder builder = new StringBuilder();  int i = 0;  foreach (var item in dic)  {  if (i > 0)  builder.Append("&");  builder.AppendFormat("{0}={1}", item.Key, item.Value);  i++;  }  byte[] data = Encoding.UTF8.GetBytes(builder.ToString());  req.ContentLength = data.Length;  using (Stream reqStream = req.GetRequestStream())  {  reqStream.Write(data, 0, data.Length);  reqStream.Close();  }  #endregion  HttpWebResponse resp = (HttpWebResponse)req.GetResponse();  Stream stream = resp.GetResponseStream();  //获取响应内容  using (StreamReader reader = new StreamReader(stream, Encoding.UTF8))  {  result = reader.ReadToEnd();  }  return result;
}  

3、不带参数的GET请求

public static string Get(string url)
{  string result = "";  HttpWebRequest req = (HttpWebRequest)WebRequest.Create(url);  HttpWebResponse resp = (HttpWebResponse)req.GetResponse();  Stream stream = resp.GetResponseStream();  try  {  //获取内容  using (StreamReader reader = new StreamReader(stream))  {  result = reader.ReadToEnd();  }  }  finally  {  stream.Close();  }  return result;
} 

4、带参数的GET请求

public static string Get(string url, Dictionary<string, string> dic)
{  string result = "";  StringBuilder builder = new StringBuilder();  builder.Append(url);  if (dic.Count > 0)  {  builder.Append("?");  int i = 0;  foreach (var item in dic)  {  if (i > 0)  builder.Append("&");  builder.AppendFormat("{0}={1}", item.Key, item.Value);  i++;  }  }  HttpWebRequest req = (HttpWebRequest)WebRequest.Create(builder.ToString());  //添加参数  HttpWebResponse resp = (HttpWebResponse)req.GetResponse();  Stream stream = resp.GetResponseStream();  try  {  //获取内容  using (StreamReader reader = new StreamReader(stream))  {  result = reader.ReadToEnd();  }  }  finally  {  stream.Close();  }  return result;
}  

5、自定义HTTP请求头

HttpWebRequest req = (HttpWebRequest)WebRequest.Create(url);
req.Method = "GET";
req.Headers["Accept-Language"] = "zh-CN,zh;q=0.8";
req.Referer = "https://www.baidu.com/";
HttpWebResponse resp = (HttpWebResponse)req.GetResponse();
Stream stream = resp.GetResponseStream();  string result = "";  //注意，此处使用的编码是：gb2312  //using (StreamReader reader = new StreamReader(stream, Encoding.Default))  using (StreamReader reader = new StreamReader(stream, Encoding.GetEncoding("gb2312")))
{  result = reader.ReadToEnd();
}