C#利用服务器实现客户端之间通信

　　这两天在学习C#，C#高级编程真的是厚厚的一本书QAQ。
　　昨天看了一下里面的通信部分(其实还没怎么看)，看了网上一些人的博客，自己在他们的博客基础上写了一个通信。
　　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，并设置多同时监听多少个Client.
　　这时，服务端在等待状态，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
1 namespace SocketServer
2 {
3     class Program
4     {
5         private static byte[] result = new byte[1024];
6
7         static Socket serverSocket;
8         private static string client;
9         private static Socket clientSocket;
10         //我这里存了两个Client，因为自己电脑开了两个Client，不会有多的
11         //理论上应该开一个Socket[]来保存信息，好用一个二元组将client的信息和连接绑定起来
12         //这样可以实现断开连接后下次登陆还是可以识别是这个Client
13         private static Socket clientSocketA=null;
14         private static Socket clientSocketB=null;
15
16         static void Main(string[] args)
17         {
18             Program.SetPort(8885);
19         }
20         private static void SetPort(int port)
21         {
22             IPAddress ip = IPAddress.Parse("127.0.0.1");//set ip
23             serverSocket = new Socket(AddressFamily.InterNetwork，
24                 SocketType.Stream， ProtocolType.Tcp);//initialize
25             serverSocket.Bind(new IPEndPoint(ip， port));//bind
26             serverSocket.Listen(10);
27             //进入监听状态
28             Console.WriteLine("监听{0}成功"， serverSocket.LocalEndPoint.ToString());
29             //开启一个线程来监听客户端连接
30             Thread myThread = new Thread(ListenClientConnect);
31             myThread.Start();
32             Console.ReadLine();
33
34         }
35         /// <summary>
36         /// 监听客户端连接
37         /// </summary>
38         private static void ListenClientConnect()
39         {
40             while (true)
41             {
42                 //Client连接上后 得到这个连接
43                 clientSocket = serverSocket.Accept();
44
45                 //这里我因为只有两个Client，所以简单写了
46                 if (clientSocketA == null)
47                 {
48                     clientSocketA = clientSocket;
49                 }
50                 else if (clientSocketB == null)
51                 {
52                     clientSocketB = clientSocket;
53                 }
54                 else
55                 {
56                     //当其中一个断开了，又重新连接时，需要再次保存连接
57                     if (clientSocketB.IsBound)
58                     {
59                         clientSocketA = clientSocketB;
60                         clientSocketB = clientSocket;
61                     }
62                     else
63                     {
64                         clientSocketB = clientSocketA;
65                         clientSocketA = clientSocket;
66                     }
67
68                 }
69                 clientSocket.Send(Encoding.ASCII.GetBytes("say hello"));
70                 //开个线程接收Client信息
71                 Thread receivedThread = new Thread(ReceiveMessage);
72                 receivedThread.Start(clientSocket);
73
74             }
75         }
76
77         private static void ReceiveMessage(object clientSocket)
78         {
79             Socket myClientSocket = (Socket) clientSocket;
80
81             while (true)
82             {
83                 try
84                 {
85                     int revceiveNumber = myClientSocket.Receive(result);
86                     //Console.WriteLine("接受客户端{0}消息{1}"， myClientSocket.RemoteEndPoint.ToString()
87                     //    ， Encoding.ASCII.GetString(result， 0， revceiveNumber));
88                     Console.WriteLine(Encoding.ASCII.GetString(result， 0， revceiveNumber));
89                     if (myClientSocket == clientSocketA)
90                     {
91                         Console.WriteLine("receive from A");
92                         if (clientSocketB!=null&&clientSocketB.IsBound)
93                         {
94                             Console.WriteLine("a IS BOUND");
95                             clientSocketB.Send(result， 0， revceiveNumber， SocketFlags.None);
96                         }
97                         else
98                         {
99                             myClientSocket.Send(Encoding.ASCII.GetBytes("the people is not online! Send Failed!"));
100                             Console.WriteLine("对方不在线上，发送失败！");
101                         }
102                     }
103                     else
104                     {
105                         Console.WriteLine("receive from B");
106                         if (clientSocketA != null && clientSocketA.IsBound)
107                         {
108                             Console.WriteLine("a IS BOUND");
109                             clientSocketA.Send(result， 0， revceiveNumber， SocketFlags.None);
110                         }
111                         else
112                         {
113                             myClientSocket.Send(Encoding.ASCII.GetBytes("the people is not online! Send Failed!"));
114                             Console.WriteLine("对方不在线上，发送失败！");
115                         }
116
117                     }
118
119                 }
120                 catch(Exception ex)
121                 {
122                     Console.WriteLine(ex.Message);
123                     myClientSocket.Shutdown(SocketShutdown.Both);
124                     myClientSocket.Close();
125                     break;
126
127                 }
128             }
129
130         }
131     }
132 }
　　Client端代码(因为都差不多 只贴一个了)
1 namespace SocketClient
2 {
3     class Program
4     {
5         private static byte[] result = new byte[1024];
6         private static Socket clientSocket;
7         private static void ListenServer()
8         {
9             while (true)
10             {
11                 result = new byte[1024];
12                 int receiveLength = clientSocket.Receive(result);
13
14                 Console.WriteLine("{0}"， Encoding.ASCII.GetString(result， 0， receiveLength));
15             }
16
17         }
18         static void Main(string[] args)
19         {
20
21             IPAddress ip = IPAddress.Parse("127.0.0.1");
22             clientSocket = new Socket(AddressFamily.InterNetwork， SocketType.Stream， ProtocolType.Tcp);
23             try
24             {
25                 clientSocket.Connect(ip， 8885);
26                 Console.WriteLine("连接成功！");
27
28             }
29             catch (Exception e)
30             {
31                 Console.WriteLine("连接失败！");
32                 return;
33             }
34             Thread threadRead = new Thread(ListenServer);
35             threadRead.Start();
36
37
38             while(true)
39             {
40                 try
41                 {
42                     Thread.Sleep(1000);
43                     string sendMessage = Console.ReadLine();
44                     clientSocket.Send(Encoding.ASCII.GetBytes("Sylvia:"+sendMessage));
45
46                 }
47                 catch (Exception ex)
48                 {
49                     clientSocket.Shutdown(SocketShutdown.Both);
50                     clientSocket.Close();
51                     break;
52                 }
53
54             }
55             Console.WriteLine("发送完毕 按回车退出");
56             Console.ReadKey();
57         }
58     }
59 }
　　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。