第一次听人用男女关系讲 N(Non-Blocking)I(进)O(出)，涨姿势了

public class NioServer {
    public void start() throws IOException {
        Selector selector = Selector.open();
        ServerSocketChannel serverSocketChannel = ServerSocketChannel.open();
        serverSocketChannel.bind(new InetSocketAddress(6789));
        serverSocketChannel.configureBlocking(false);
        serverSocketChannel.register(selector, SelectionKey.OP_ACCEPT);
        System.out.println("服务器启动成功");
        while (true) {
            selector.select();
            Set<SelectionKey> selectionKeys = selector.selectedKeys();
            Iterator<SelectionKey> iterator = selectionKeys.iterator();
            while (iterator.hasNext()) {
                SelectionKey selectionKey = iterator.next();
                if (selectionKey.isAcceptable()) {
                    iterator.remove();
                    handleAccept(serverSocketChannel, selector);
                } else if (selectionKey.isReadable()) {
                    handleRead(selectionKey);
                } else {
                    System.out.println("其他请求");
                }
            }
        }
    }

    private void handleRead(SelectionKey selectionKey) throws IOException {
        SocketChannel socketChannel = (SocketChannel) selectionKey.channel();
        ByteBuffer byteBuffer = ByteBuffer.allocate(1024);
        StringBuilder request = new StringBuilder();
        while (socketChannel.read(byteBuffer) > 0) {
            byteBuffer.flip();
            request.append(StandardCharsets.UTF_8.decode(byteBuffer));
        }
        if (request.length() > 0) {
            System.out.println("服务端收到消息：" + request.toString());
        }
    }

    private void handleAccept(ServerSocketChannel serverSocketChannel, Selector selector) throws IOException {
        SocketChannel socketChannel = serverSocketChannel.accept();
        socketChannel.configureBlocking(false);
        socketChannel.register(selector, SelectionKey.OP_READ);
        System.out.println("有新人进入聊天室");
        socketChannel.write(StandardCharsets.UTF_8.encode("进入聊天室，现在可以聊天了"));
    }

    public static void main(String[] args) throws IOException {
        new NioServer().start();
    }
}

public class NioClient {
    public void start() throws IOException {
        SocketChannel socketChannel = SocketChannel.open(new InetSocketAddress(6789));
        Selector selector = Selector.open();
        socketChannel.configureBlocking(false);
        socketChannel.register(selector, SelectionKey.OP_READ);
        new Thread(new NioClientHandler(selector)).start();
        Scanner scanner = new Scanner(System.in);
        while (scanner.hasNextLine()) {
            String request = scanner.nextLine();
            if (request != null && request.length() > 0) {
                socketChannel.write(StandardCharsets.UTF_8.encode(request));
            }
        }
    }

    public static void main(String[] args) throws IOException {
        new NioClient().start();
    }

    private class NioClientHandler implements Runnable {
        private Selector selector;

        public NioClientHandler(Selector selector) {
            this.selector = selector;
        }

        @Override
        public void run() {
            try {
                while (true) {
                    selector.select();
                    Set<SelectionKey> selectionKeys = selector.selectedKeys();

                    Iterator iterator = selectionKeys.iterator();
                    while (iterator.hasNext()) {
                        SelectionKey selectionKey = (SelectionKey) iterator.next();
                        SocketChannel socketChannel = (SocketChannel) selectionKey.channel();
                        ByteBuffer byteBuffer = ByteBuffer.allocate(1024);
                        StringBuilder response = new StringBuilder();
                        while (socketChannel.read(byteBuffer) > 0) {
                            byteBuffer.flip();
                            response.append(StandardCharsets.UTF_8.decode(byteBuffer));
                        }
                        if (response.length() > 0) {
                            System.out.println("接收服务端消息:" + response);
                        }
                    }
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }
}

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