可以使用org.java_websocket库来实现WebSocket服务器，并通过broadcast方法实现广播

java实现

import org.java_websocket.WebSocket;
import org.java_websocket.handshake.ClientHandshake;
import org.java_websocket.server.WebSocketServer;
import java.net.InetSocketAddress;
import java.io.IOException;

public class BroadcastWebSocketServer extends WebSocketServer {
    public BroadcastWebSocketServer(int port) throws IOException {
        super(new InetSocketAddress(port));
    }

    @Override
    public void onOpen(WebSocket conn, ClientHandshake handshake) {
        conn.send("Welcome to the server!");
        broadcast("New connection: " + handshake.getResourceDescriptor());
    }

    @Override
    public void onClose(WebSocket conn, int code, String reason, boolean remote) {
        broadcast(conn.getRemoteSocketAddress().getAddress().getHostAddress() + " has left the room!");
    }

    @Override
    public void onMessage(WebSocket conn, String message) {
        broadcast("Message from " + conn.getRemoteSocketAddress().getAddress().getHostAddress() + ": " + message);
    }

    @Override
    public void onError(WebSocket conn, Exception ex) {
        ex.printStackTrace();
    }

    @Override
    public void onStart() {
        System.out.println("Server started!");
    }
}