用Java的NIO技术写一个Knock Knock游戏的客户机/服务器代码

好的，我可以为您提供一个基本的Knock Knock游戏的客户机/服务器代码。此代码使用Java NIO技术来处理客户端和服务器端之间的通信。

这是服务器端的代码：

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

public class KnockKnockServer {
    private static final int BUFFER_SIZE = 1024;
    private static final int TIMEOUT = 3000;

    public static void main(String[] args) throws IOException {
        int port = 8080;
        if (args.length > 0) {
            port = Integer.parseInt(args[0]);
        }

        Selector selector = Selector.open();
        ServerSocketChannel serverSocketChannel = ServerSocketChannel.open();
        serverSocketChannel.socket().bind(new InetSocketAddress(port));
        serverSocketChannel.configureBlocking(false);
        serverSocketChannel.register(selector, SelectionKey.OP_ACCEPT);

        while (true) {
            if (selector.select(TIMEOUT) == 0) {
                continue;
            }
            Iterator<SelectionKey> iterator = selector.selectedKeys().iterator();
            while (iterator.hasNext()) {
                SelectionKey key = iterator.next();
                if (key.isAcceptable()) {
                    handleAccept(key, selector);
                }
                if (key.isReadable()) {
                    handleRead(key, selector);
                }
                iterator.remove();
            }
        }
    }

    private static void handleAccept(SelectionKey key, Selector selector) throws IOException {
        ServerSocketChannel serverSocketChannel = (ServerSocketChannel) key.channel();
        SocketChannel socketChannel = serverSocketChannel.accept();
        socketChannel.configureBlocking(false);
        socketChannel.register(selector, SelectionKey.OP_READ, ByteBuffer.allocate(BUFFER_SIZE));
    }

    private static void handleRead(SelectionKey key, Selector selector) throws IOException {
        SocketChannel socketChannel = (SocketChannel) key.channel();
        ByteBuffer buffer = (ByteBuffer) key.attachment();
        int bytesRead = socketChannel.read(buffer);
        if (bytesRead == -1) {
            socketChannel.close();
            return;
        }
        if (bytesRead > 0) {
            String message = new String(buffer.array()).trim();
            if (message.equalsIgnoreCase("Knock Knock")) {
                buffer.clear();
                buffer.put("Who's there?".getBytes());
                buffer.flip();
                socketChannel.write(buffer);
            } else if (message.equalsIgnoreCase("Boo")) {
                buffer.clear();
                buffer.put("Don't cry, it's only a joke.".getBytes());
                buffer.flip();
                socketChannel.write(buffer);
            } else {
                buffer.clear();
                buffer.put("You're supposed to say \"Knock Knock\"!".getBytes());
                buffer.flip();
                socketChannel.write(buffer);
            }
        }
    }
}

这是客户端的代码：

import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.SocketChannel;
import java.util.Scanner;

public class KnockKnockClient {
    private static final int BUFFER_SIZE = 1024;

    public static void main(String[] args) throws IOException {
        String host = "localhost";
        int port = 8080;
        if (args.length > 0) {
            host = args[0];
        }
        if (args.length > 1) {
            port = Integer.parseInt(args[1]);
        }

        InetSocketAddress serverAddress = new InetSocketAddress(host, port);
        SocketChannel socketChannel = SocketChannel.open(serverAddress);
        socketChannel.configureBlocking(false);

        ByteBuffer buffer = ByteBuffer.allocate(BUFFER_SIZE);
        Scanner scanner = new Scanner(System.in);
        while (true) {
            String message = scanner.nextLine();
            buffer.clear();
            buffer.put(message.getBytes());
            buffer.flip();
            socketChannel.write(buffer);

            buffer.clear();
            int bytesRead = socketChannel.read(buffer);
            if (bytesRead == -1) {
                socketChannel.close();
                return;
            }
            if (bytesRead > 0) {
                String response = new String(buffer.array()).trim();
                System.out.println(response);
            }
        }
    }
}

运行服务器端代码后，可以在另一个终端中运行客户端代码。在客户端中输入“Knock Knock”，服务器将响应“Who's there?”。然后，在客户端中输入“Boo”，服务器将响应“Don't cry, it's only a joke.”。如果客户端输入其他内容，则服务器将响应“You're supposed to say \"Knock Knock\"!”。