.Net HttpWebRequest 方式 访问服务器

string responseData = "";
System.Net.HttpWebRequest request = (System.Net.HttpWebRequest)System.Net.WebRequest.Create("http://xxx.com/aaa");
//接收响应
System.Net.HttpWebResponse response = (System.Net.HttpWebResponse)request.GetResponse();
//输出流
Stream stream = response.GetResponseStream();
byte[] rsByte = new Byte[response.ContentLength];  //save data in the stream
try
{
stream.Read(rsByte, 0, (int)response.ContentLength);
responseData = System.Text.Encoding.Default.GetString(rsByte, 0, rsByte.Length).ToString();//直接获取到返回的内容.
}
catch (Exception exp)
{ }
return responseData;

//使用FileStream可以保存到文件
 FileStream fs = new FileStream("D:\\a.txt", FileMode.Create);
        System.Net.HttpWebRequest request = (System.Net.HttpWebRequest)System.Net.WebRequest.Create("http://xxx.com/aaa");
        System.Net.HttpWebResponse response = (System.Net.HttpWebResponse)request.GetResponse();
        Stream stream = response.GetResponseStream();

        int bufferSize = 2048;
        byte[] bytes = new byte[bufferSize];
        try
        {
            int length = stream.Read(bytes, 0, bufferSize);
            while (length > 0)
            {
                fs.Write(bytes, 0, length);
                length = stream.Read(bytes, 0, bufferSize);
            }
            stream.Close();
            fs.Close();
            response.Close();
            return "";
        }
        catch (Exception ex)
        {
          
        }