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
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，最好用一个二元组将client的信息和连接绑定起来
12 //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
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，所以就简单写了
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 就只贴一个了)
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。
这个大家就自己尝试吧