使用C#开发一个简单的P2P应用(2)

来源：qqread 作者：出处：巧巧读书 2007-03-22 进入讨论组

关键词：
networks
server
access
dns
ssl

C#语言由于其对网络功能良好的支持，特别是内置地支持TCPListener和TCPClient这二个类，使得利用它开发P2P应用程序变得非常容易。下面就是一个使用C#开发的P2P应用的例子：
public MyTcpListener(int port) : base(port)

  {
  }
  public void StopMe()
  {
  if ( this.Server != null )
  {
  this.Server.Close();
  }
  }
  }
  public class Transfer
  {
  MyTcpListener tcpl;
  public Transfer()
  {
  OptionsLoader ol = new OptionsLoader();
  int port = 8081;
  if (ol.Port > 0)
  {
  port = ol.Port;
  }
  else
  {
  port = 8081;
  }
  this.tcpl = new MyTcpListener(port);
  }
  public void TransferShutdown()
  {
  tcpl.StopMe();
  }
  public void ListenForPeers()
  {
  try
  {
  Encoding ASCII = Encoding.ASCII;
  tcpl.Start();
  while (true)
  {
  // 在有连接之前，Accept将处于阻塞状态
  Socket s = tcpl.AcceptSocket();
  NetworkStream DataStream = new NetworkStream(s);
  String filename;
  Byte[] Buffer = new Byte[256];
  DataStream.Read(Buffer, 0, 256);
  filename = Encoding.ASCII.GetString(Buffer);
  StringBuilder sbFileName = new StringBuilder(filename);
  StringBuilder sbFileName2 = sbFileName.Replace("\", "\\");
  FileStream fs = new FileStream(sbFileName2.ToString(), FileMode.Open, FileAccess.Read);
  BinaryReader reader = new BinaryReader(fs);
  byte[] bytes = new byte[1024];
  int read;
  while((read = reader.Read(bytes, 0, bytes.Length)) != 0)
  {
  DataStream.Write(bytes, 0, read);
  }
  reader.Close();
  DataStream.Flush();
  DataStream.Close();
  }
  }
  catch(SocketException ex)
  {
  MessageBox.Show(ex.ToString());
  }
  }
  public void DownloadToClient(String server, string remotefilename, string localfilename)
  {
  try
  {
  TcpClient tcpc = new TcpClient();
  Byte[] read = new Byte[1024];
  OptionsLoader ol = new OptionsLoader();
  int port = 0;
  if (ol.Port > 0)
  {
  port = ol.Port;
  }
  else
  {
  // 缺省的端口号，可以设置为使用的端口号
  port = 8081;
  }
  // 尝试与服务器连接
  IPHostEntry IPHost = Dns.Resolve(server);
  string []aliases = IPHost.Aliases;
  IPAddress[] addr = IPHost.AddressList;
  IPEndPoint ep = new IPEndPoint(addr[0], port);
  tcpc.Connect(ep);
  // 获得流对象
  Stream s = tcpc.GetStream();
  Byte[] b = Encoding.ASCII.GetBytes(remotefilename.ToCharArray());
  s.Write( b, 0, b.Length );
  int bytes;
  FileStream fs = new FileStream(localfilename, FileMode.OpenOrCreate);
  BinaryWriter w = new BinaryWriter(fs);
  // 读取流对象，并将其转换为ASCII码
  while( (bytes = s.Read(read, 0, read.Length)) != 0)
  {
  w.Write(read, 0, bytes);
  read = new Byte[1024];
  }
  tcpc.Close();
  w.Close();
  fs.Close();
  }
  catch(Exception ex)
  {
  throw new Exception(ex.ToString());
  }
  }
  }
  }观看地址： http://www.qqread.com/csharp/u303922.html