java写一段websocket的服务端

你好，以下是一段使用 Java 编写的 WebSocket 服务端代码：

import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;
import java.nio.charset.Charset;
import java.util.Iterator;
import java.util.Set;

public class WebSocketServer {
    private static final int PORT = 808;
    private static final Charset CHARSET = Charset.forName("UTF-8");

    public static void main(String[] args) throws IOException {
        ServerSocketChannel serverSocketChannel = ServerSocketChannel.open();
        serverSocketChannel.socket().bind(new InetSocketAddress(PORT));
        serverSocketChannel.configureBlocking(false);

        Selector selector = Selector.open();
        serverSocketChannel.register(selector, SelectionKey.OP_ACCEPT);

        while (true) {
            int readyChannels = selector.select();
            if (readyChannels == ) {
                continue;
            }

            Set<SelectionKey> selectedKeys = selector.selectedKeys();
            Iterator<SelectionKey> keyIterator = selectedKeys.iterator();

            while (keyIterator.hasNext()) {
                SelectionKey key = keyIterator.next();

                if (key.isAcceptable()) {
                    ServerSocketChannel serverChannel = (ServerSocketChannel) key.channel();
                    SocketChannel socketChannel = serverChannel.accept();
                    socketChannel.configureBlocking(false);
                    socketChannel.register(selector, SelectionKey.OP_READ);
                } else if (key.isReadable()) {
                    SocketChannel socketChannel = (SocketChannel) key.channel();
                    ByteBuffer buffer = ByteBuffer.allocate(1024);
                    int bytesRead = socketChannel.read(buffer);
                    if (bytesRead == -1) {
                        socketChannel.close();
                        continue;
                    }
                    buffer.flip();
                    CharBuffer charBuffer = CHARSET.decode(buffer);
                    String message = charBuffer.toString().trim();
                    System.out.println("Received message: " + message);
                    socketChannel.write(CHARSET.encode("Server received your message: " + message));
                }

                keyIterator.remove();
            }
        }
    }
}

以上代码实现了一个简单的 WebSocket 服务端，监听 808 端口，接收客户端发送的消息并回复。当客户端连接时，服务端会注册一个 OP_ACCEPT 事件，当客户端发送消息时，服务端会注册一个 OP_READ 事件。在 OP_READ 事件中，服务端会读取客户端发送的消息并回复。