websocket实现消息广播 java版

在Java中实现WebSocket消息广播可以使用Java-WebSocket库。下面是一个简单的示例代码：

import java.net.InetSocketAddress;
import java.net.UnknownHostException;
import java.util.Collection;
import java.util.concurrent.CopyOnWriteArrayList;
import org.java_websocket.WebSocket;
import org.java_websocket.handshake.ClientHandshake;
import org.java_websocket.server.WebSocketServer;

public class WebSocketBroadcastServer extends WebSocketServer {

    private Collection<WebSocket> clients;

    public WebSocketBroadcastServer(int port) throws UnknownHostException {
        super(new InetSocketAddress(port));
        clients = new CopyOnWriteArrayList<>();
    }

    @Override
    public void onOpen(WebSocket conn, ClientHandshake handshake) {
        clients.add(conn);
        System.out.println("New connection from " + conn.getRemoteSocketAddress().getAddress().getHostAddress());
    }

    @Override
    public void onClose(WebSocket conn, int code, String reason, boolean remote) {
        clients.remove(conn);
        System.out.println("Closed connection to " + conn.getRemoteSocketAddress().getAddress().getHostAddress());
    }

    @Override
    public void onMessage(WebSocket conn, String message) {
        System.out.println("Received message: " + message);
        broadcast(message);
    }

    @Override
    public void onError(WebSocket conn, Exception ex) {
        System.err.println("Error occurred on connection " + conn.getRemoteSocketAddress().getAddress().getHostAddress() + ": " + ex);
    }

    private void broadcast(String message) {
        for (WebSocket client : clients) {
            client.send(message);
        }
        System.out.println("Message broadcasted to " + clients.size() + " clients");
    }

    public static void main(String[] args) throws UnknownHostException {
        int port = 8080;
        WebSocketBroadcastServer server = new WebSocketBroadcastServer(port);
        server.start();
        System.out.println("WebSocket server started on port " + port);
    }
}

这个示例代码创建了一个WebSocket服务器，监听指定端口（8080）。当有新连接加入时，它将追踪所有连接的客户端，并在收到消息时将消息广播给所有客户端。

你可以根据自己的需求修改和扩展这个示例代码。