我刚刚开始使用 C# 进行套接字编程，现在有点被这个问题困住了。 如何在不为每个客户端创建线程的情况下在单个服务器上处理多个客户端？

当有 10 个客户端时，每个客户端的一个线程工作正常，但如果客户端数量增加到 1000 个客户端，是否为每个客户端创建一个线程是否可取？如果还有其他方法可以做到这一点，有人可以告诉我吗？

最佳答案

尝试使用异步服务器。 以下示例程序创建了一个服务器，用于接收来自客户端的连接请求。服务器是用异步套接字构建的，因此服务器应用程序的执行在等待来自客户端的连接时不会被挂起。应用程序从客户端接收一个字符串，在控制台上显示该字符串，然后将该字符串回显给客户端。来自客户端的字符串必须包含字符串 <EOF>表示消息结束。

using System;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading;

// State object for reading client data asynchronously
public class StateObject {
    // Client  socket.
    public Socket workSocket = null;
    // Size of receive buffer.
    public const int BufferSize = 1024;
    // Receive buffer.
    public byte[] buffer = new byte[BufferSize];
    // Received data string.
    public StringBuilder sb = new StringBuilder();  
}

public class AsynchronousSocketListener {
    // Thread signal.
    public static ManualResetEvent allDone = new ManualResetEvent(false);

    public AsynchronousSocketListener() {
    }

    public static void StartListening() {
        // Data buffer for incoming data.
        byte[] bytes = new Byte[1024];

        // Establish the local endpoint for the socket.
        // The DNS name of the computer
        // running the listener is "host.contoso.com".
        IPHostEntry ipHostInfo = Dns.Resolve(Dns.GetHostName());
        IPAddress ipAddress = ipHostInfo.AddressList[0];
        IPEndPoint localEndPoint = new IPEndPoint(ipAddress, 11000);

        // Create a TCP/IP socket.
        Socket listener = new Socket(AddressFamily.InterNetwork,
            SocketType.Stream, ProtocolType.Tcp );

        // Bind the socket to the local endpoint and listen for incoming connections.
        try {
            listener.Bind(localEndPoint);
            listener.Listen(100);

            while (true) {
                // Set the event to nonsignaled state.
                allDone.Reset();

                // Start an asynchronous socket to listen for connections.
                Console.WriteLine("Waiting for a connection...");
                listener.BeginAccept( 
                    new AsyncCallback(AcceptCallback),
                    listener );

                // Wait until a connection is made before continuing.
                allDone.WaitOne();
            }

        } catch (Exception e) {
            Console.WriteLine(e.ToString());
        }

        Console.WriteLine("\nPress ENTER to continue...");
        Console.Read();

    }

    public static void AcceptCallback(IAsyncResult ar) {
        // Signal the main thread to continue.
        allDone.Set();

        // Get the socket that handles the client request.
        Socket listener = (Socket) ar.AsyncState;
        Socket handler = listener.EndAccept(ar);

        // Create the state object.
        StateObject state = new StateObject();
        state.workSocket = handler;
        handler.BeginReceive( state.buffer, 0, StateObject.BufferSize, 0,
            new AsyncCallback(ReadCallback), state);
    }

    public static void ReadCallback(IAsyncResult ar) {
        String content = String.Empty;

        // Retrieve the state object and the handler socket
        // from the asynchronous state object.
        StateObject state = (StateObject) ar.AsyncState;
        Socket handler = state.workSocket;

        // Read data from the client socket. 
        int bytesRead = handler.EndReceive(ar);

        if (bytesRead > 0) {
            // There  might be more data, so store the data received so far.
            state.sb.Append(Encoding.ASCII.GetString(
                state.buffer,0,bytesRead));

            // Check for end-of-file tag. If it is not there, read 
            // more data.
            content = state.sb.ToString();
            if (content.IndexOf("<EOF>") > -1) {
                // All the data has been read from the 
                // client. Display it on the console.
                Console.WriteLine("Read {0} bytes from socket. \n Data : {1}",
                    content.Length, content );
                // Echo the data back to the client.
                Send(handler, content);
            } else {
                // Not all data received. Get more.
                handler.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0,
                new AsyncCallback(ReadCallback), state);
            }
        }
    }

    private static void Send(Socket handler, String data) {
        // Convert the string data to byte data using ASCII encoding.

        byte[] byteData = Encoding.ASCII.GetBytes(data);

        // Begin sending the data to the remote device.
        handler.BeginSend(byteData, 0, byteData.Length, 0,
            new AsyncCallback(SendCallback), handler);
    }

    private static void SendCallback(IAsyncResult ar) {
        try {
            // Retrieve the socket from the state object.
            Socket handler = (Socket) ar.AsyncState;

            // Complete sending the data to the remote device.
            int bytesSent = handler.EndSend(ar);
            Console.WriteLine("Sent {0} bytes to client.", bytesSent);

            handler.Shutdown(SocketShutdown.Both);
            handler.Close();

        } catch (Exception e) {
            Console.WriteLine(e.ToString());
        }
    }   

    public static int Main(String[] args) {
        StartListening();
        return 0;
    }
}

这将是最好的解决方案。

关于c# - Socket编程多客户端一台服务器，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/14974404/