给我代码

好的，这里是一个基于Java Socket的简单多客户端聊天程序的示例代码，仅供参考：

Server端代码：

import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.ArrayList;
import java.util.List;

public class ChatServer {
    private ServerSocket serverSocket;
    private List<Socket> sockets;

    public ChatServer(int port) throws IOException {
        serverSocket = new ServerSocket(port);
        sockets = new ArrayList<>();
    }

    public void start() throws IOException {
        System.out.println("Server started.");
        while (true) {
            Socket socket = serverSocket.accept();
            System.out.println("New client connected: " + socket);
            sockets.add(socket);
            new ClientHandler(socket).start();
        }
    }

    private class ClientHandler extends Thread {
        private Socket socket;

        public ClientHandler(Socket socket) {
            this.socket = socket;
        }

        @Override
        public void run() {
            try {
                while (true) {
                    String message = Utils.receiveMessage(socket);
                    System.out.println("Received message: " + message);
                    broadcast(message);
                }
            } catch (IOException e) {
                System.out.println("Client disconnected: " + socket);
                sockets.remove(socket);
            }
        }

        private void broadcast(String message) throws IOException {
            for (Socket s : sockets) {
                if (s != socket) {
                    Utils.sendMessage(s, message);
                }
            }
        }
    }

    public static void main(String[] args) throws IOException {
        ChatServer server = new ChatServer(8080);
        server.start();
    }
}

Client端代码：

import java.io.IOException;
import java.net.Socket;
import java.util.Scanner;

public class ChatClient {
    private Socket socket;

    public ChatClient(String host, int port) throws IOException {
        socket = new Socket(host, port);
    }

    public void start() {
        new Thread(() -> {
            try {
                while (true) {
                    String message = Utils.receiveMessage(socket);
                    System.out.println("Received message: " + message);
                }
            } catch (IOException e) {
                System.out.println("Server disconnected.");
            }
        }).start();

        Scanner scanner = new Scanner(System.in);
        while (true) {
            String message = scanner.nextLine();
            Utils.sendMessage(socket, message);
        }
    }

    public static void main(String[] args) throws IOException {
        ChatClient client = new ChatClient("localhost", 8080);
        client.start();
    }
}

Utils类中包含了一些常用的读写操作，这里不再赘述。需要注意的是，这个示例代码中没有对消息格式和协议进行定义，需要根据实际情况进行调整。