Socket

来源：http://blog.sina.com.cn/s/blog_493309600100clrw.html

TCP与UDP区别

TCP---传输控制协议,提供的是面向连接、可靠的字节流服务。当客户和服务器彼此交换数据前，必须先在双方之间建立一个TCP连接，之后才能传输数据。TCP提供超时重发，丢弃重复数据，检验数据，流量控制等功能，保证数据能从一端传到另一端。
UDP---用户数据报协议，是一个简单的面向数据报的运输层协议。UDP不提供可靠性，它只是把应用程序传给IP层的数据报发送出去，但是并不能保证它们能到达目的地。由于UDP在传输数据报前不用在客户和服务器之间建立一个连接，且没有超时重发等机制，故而传输速度很快

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来源：http://www.jb51.net/article/72313.htm

本文实例讲述了C#中Socket通信用法。分享给大家供大家参考。具体如下：

一、UDP方式：

服务器端代码:

static void Main(string[] args)

{

  int recv;

  byte[] data = new byte[1024];

  IPEndPoint ipep = new IPEndPoint(IPAddress.Any, 9050);//定义一网络端点

  Socket newsock = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);//定义一个Socket

  newsock.Bind(ipep);//Socket与本地的一个终结点相关联

  Console.WriteLine("Waiting for a client..");

  IPEndPoint sender = new IPEndPoint(IPAddress.Any, 0);//定义要发送的计算机的地址

  EndPoint Remote = (EndPoint)(sender);//

  recv = newsock.ReceiveFrom(data, ref Remote);//接受数据     

  Console.WriteLine("Message received from{0}:", Remote.ToString());

  Console.WriteLine(Encoding.ASCII.GetString(data, 0, recv));

  string welcome = "Welcome to my test server!";

  data = Encoding.ASCII.GetBytes(welcome);

  newsock.SendTo(data, data.Length, SocketFlags.None, Remote);

  while (true)

  {

    data = new byte[1024];

    recv = newsock.ReceiveFrom(data, ref Remote);

    Console.WriteLine(Encoding.ASCII.GetString(data, 0, recv));

    newsock.SendTo(data, recv, SocketFlags.None, Remote);

  }

}

客户端代码:

void MainInfo()

{

  byte[] data = new byte[1024];//定义一个数组用来做数据的缓冲区

  string input, stringData;

  IPEndPoint ipep = new IPEndPoint(IPAddress.Parse("192.168.1.21"), 9050);

  Socket server = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);

  string welcome = "Hello,are you there?";

  data = Encoding.ASCII.GetBytes(welcome);

  server.SendTo(data, data.Length, SocketFlags.None, ipep);//将数据发送到指定的终结点

  IPEndPoint sender = new IPEndPoint(IPAddress.Any, 0);

  EndPoint Remote = (EndPoint)sender;

  data = new byte[1024];

  int recv = server.ReceiveFrom(data, ref Remote);//接受来自服务器的数据

  Console.WriteLine("Message received from{0}:", Remote.ToString());

  Console.WriteLine(Encoding.ASCII.GetString(data, 0, recv));

  while (true)//读取数据

  {

    input = richTextBox1.Text;//从键盘读取数据

    if (input == "text")//结束标记

    {

      break;

    }

    server.SendTo(Encoding.ASCII.GetBytes(input), Remote);//将数据发送到指定的终结点Remote

    data = new byte[1024];

    recv = server.ReceiveFrom(data, ref Remote);//从Remote接受数据

    stringData = Encoding.ASCII.GetString(data, 0, recv);

    Console.WriteLine(stringData);

  }

  Console.WriteLine("Stopping client");

  server.Close();

}

二、TCP方式:

服务器端代码:

Socket serverSocket = null;

Thread clientThread = null;

Socket clientSocket = null;

Thread thread = null;

IPAddress ips = null;

PEndPoint ipep = null;

void ServerStart()

{

  ips = Dns.GetHostAddresses(Dns.GetHostName())[0];

  //创建IPEndPoint实例 

  ipep = new IPEndPoint(ips, 9050);

  //创建一个套接字 

  serverSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);

  serverSocket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, true);

  //将所创建的套接字与IPEndPoint绑定 

  serverSocket.Bind(ipep);

  //设置套接字为收听模式 

  serverSocket.Listen(20);

  while (listenalive)

  {

    try

    {

      //在套接字上接收接入的连接 

      clientSocket = serverSocket.Accept();

      clientThread = new Thread(new ParameterizedThreadStart(ReceiveData));

      clientThread.Start(clientSocket);

    }

    catch (Exception ex)

    {

      WriteErrorLog(ex.Message);

      serverSocket.Close();

      serverSocket = null;

    }

  }

}

static void ReceiveData(object obj)

{

  bool keepalive = true;

  Socket s = obj as Socket;

  Byte[] buffer = new Byte[1024];

  //根据收听到的客户端套接字向客户端发送信息 

  IPEndPoint clientep = (IPEndPoint)s.RemoteEndPoint;

  Console.WriteLine("客户端ip:" + clientep.Address + " 端口:" + clientep.Port);

  string welcome = "连接服务器成功";

  buffer = System.Text.Encoding.Unicode.GetBytes(welcome);

  //向客户端发送“连接服务器成功”消息

  s.Send(buffer, buffer.Length, SocketFlags.None);

  buffer = new Byte[1024];

  int bufLen = 0;

  string content = string.Empty;

  while (true)

  {

    //在套接字上接收客户端发送的信息 

    bufLen = 0;

    try

    {

      bufLen = s.Receive(buffer);

      if (bufLen == 0)

      {

        break;

      }

      content += System.Text.Encoding.Unicode.GetString(buffer, 0, bufLen);

    }

    catch (Exception ex)

    {

      break; ;

    }

  }

  Send(s, content);

  s = null;

  buffer = null;

  clientep = null;

  Thread.CurrentThread.Abort();

}

客户端代码:

void Send(string content)

{

  byte[] data = new byte[1024];

  newclient = new System.Net.Sockets.Socket(System.Net.Sockets.AddressFamily.InterNetwork, System.Net.Sockets.SocketType.Stream, System.Net.Sockets.ProtocolType.Tcp);

  ie = new System.Net.IPEndPoint(System.Net.IPAddress.Parse(ipadd), port);//服务器的IP和端口

  try

  {

    //因为客户端只是用来向特定的服务器发送信息，所以不需要绑定本机的IP和端口。不需要监听。

    newclient.Connect(ie);

  }

  catch (System.Net.Sockets.SocketException e)

  {

    Console.WriteLine(e.ToString());

    return;

  }

  int recv = newclient.Receive(data);

  //连接服务器成功

  string stringdata = System.Text.Encoding.Unicode.GetString(data, 0, recv);

  if (stringdata == "连接服务器成功")

  {

    newclient.Send(System.Text.Encoding.Unicode.GetBytes(content));

    newclient.Shutdown(System.Net.Sockets.SocketShutdown.Send);

    data = new byte[1024];

    recv = newclient.Receive(data);

    string result = System.Text.Encoding.Unicode.GetString(data, 0, recv);    

    newclient.Shutdown(System.Net.Sockets.SocketShutdown.Receive);

    newclient.Close();

    MessageBox.Show(result);

  }

  else

  {

    MessageBox.Show("连接服务器失败", "友情提示");

  }

}