C#利用服务器实现客户端之间通信

先来讲述下我自己对于整个Socket通信过程的理解，毕竟初学，说错见谅，知道错了会改正~ 

首先在服务端新建一个serverSocket，对其进行初始化（一般包含AddressFamily:IP地址类型，SocketType:Socket传输数据方式，ProtoType:传输协议）; 

接着我们要设置server端要绑定的IP:port;然后开始监听，并设置最多同时监听多少个Client.

这时，服务端就在等待状态，直到某一个Client连接到这个ip:port上，这时serverSocket.Accept()工作，获得这个连接。（此时的连接是有地址信息的哦！记得保存） 

获得连接之后，server就可以和这个Client进行通信了,当加入第二个Client（我们称其为ClientB）时，Server接收到ClientB的消息，可以将这个消息转发给前一个Client（我们称其为ClientA），当受到ClientA的消息，也可以转发给ClientB。这样就实现了Clients之间的通信了。（重点在保存连接信息！！）

那么现在贴上代码讲解：

Server端代码 

namespace SocketServer { class Program { private static byte[] result = new byte[1024]; static Socket serverSocket; private static string client; private static Socket clientSocket; //我这里存了两个Client，因为自己电脑开了两个Client，不会有多的 //理论上应该开一个Socket[]来保存信息，最好用一个二元组将client的信息和连接绑定起来 //这样就可以实现断开连接后下次登陆还是可以识别是这个Client private static Socket clientSocketA=null; private static Socket clientSocketB=null; static void Main(string[] args) { Program.SetPort(8885); } private static void SetPort(int port) { IPAddress ip = IPAddress.Parse("127.0.0.1");//set ip serverSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);//initialize serverSocket.Bind(new IPEndPoint(ip, port));//bind serverSocket.Listen(10); //进入监听状态 Console.WriteLine("监听{0}成功", serverSocket.LocalEndPoint.ToString()); //开启一个线程来监听客户端连接 Thread myThread = new Thread(ListenClientConnect); myThread.Start(); Console.ReadLine(); } /// <summary> /// 监听客户端连接 /// </summary> private static void ListenClientConnect() { while (true) { //Client连接上后 得到这个连接 clientSocket = serverSocket.Accept(); //这里我因为只有两个Client，所以就简单写了 if (clientSocketA == null) { clientSocketA = clientSocket; } else if (clientSocketB == null) { clientSocketB = clientSocket; } else { //当其中一个断开了，又重新连接时，需要再次保存连接 if (clientSocketB.IsBound) { clientSocketA = clientSocketB; clientSocketB = clientSocket; } else { clientSocketB = clientSocketA; clientSocketA = clientSocket; } } clientSocket.Send(Encoding.ASCII.GetBytes("say hello")); //开个线程接收Client信息 Thread receivedThread = new Thread(ReceiveMessage); receivedThread.Start(clientSocket); } } private static void ReceiveMessage(object clientSocket) { Socket myClientSocket = (Socket) clientSocket; while (true) { try { int revceiveNumber = myClientSocket.Receive(result); //Console.WriteLine("接受客户端{0}消息{1}", myClientSocket.RemoteEndPoint.ToString() // , Encoding.ASCII.GetString(result, 0, revceiveNumber)); Console.WriteLine(Encoding.ASCII.GetString(result, 0, revceiveNumber)); if (myClientSocket == clientSocketA) { Console.WriteLine("receive from A"); if (clientSocketB!=null&&clientSocketB.IsBound) { Console.WriteLine("a IS BOUND"); clientSocketB.Send(result, 0, revceiveNumber, SocketFlags.None); } else { myClientSocket.Send(Encoding.ASCII.GetBytes("the people is not online! Send Failed!")); Console.WriteLine("对方不在线上，发送失败！"); } } else { Console.WriteLine("receive from B"); if (clientSocketA != null && clientSocketA.IsBound) { Console.WriteLine("a IS BOUND"); clientSocketA.Send(result, 0, revceiveNumber, SocketFlags.None); } else { myClientSocket.Send(Encoding.ASCII.GetBytes("the people is not online! Send Failed!")); Console.WriteLine("对方不在线上，发送失败！"); } } } catch(Exception ex) { Console.WriteLine(ex.Message); myClientSocket.Shutdown(SocketShutdown.Both); myClientSocket.Close(); break; } } } } }

Client端代码(因为都差不多 就只贴一个了) 

namespace SocketClient { class Program { private static byte[] result = new byte[1024]; private static Socket clientSocket; private static void ListenServer() { while (true) { result = new byte[1024]; int receiveLength = clientSocket.Receive(result); Console.WriteLine("{0}", Encoding.ASCII.GetString(result, 0, receiveLength)); } } static void Main(string[] args) { IPAddress ip = IPAddress.Parse("127.0.0.1"); clientSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp); try { clientSocket.Connect(ip, 8885); Console.WriteLine("连接成功！"); } catch (Exception e) { Console.WriteLine("连接失败！"); return; } Thread threadRead = new Thread(ListenServer); threadRead.Start(); while(true) { try { Thread.Sleep(1000); string sendMessage = Console.ReadLine(); clientSocket.Send(Encoding.ASCII.GetBytes("Sylvia:"+sendMessage)); } catch (Exception ex) { clientSocket.Shutdown(SocketShutdown.Both); clientSocket.Close(); break; } } Console.WriteLine("发送完毕 按回车退出"); Console.ReadKey(); } } }

写的时候要特别注意一下Send信息的时候，注意byte[]的传输大小，很容易变成byte[]数组的大小而不是内容的大小。 

这个大家就自己尝试吧。

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。

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