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。