原生NIO cs demo

public static void startServer()throws Exception {
    // 1 获取服务端通道
    ServerSocketChannel serverSocketChannel = ServerSocketChannel.open();
    // 2 切换非阻塞模式
    serverSocketChannel.configureBlocking(false);
    // 3 创建buffer
    ByteBuffer byteBuffer = ByteBuffer.allocate(1024);
    // 4 绑定端口号
    serverSocketChannel.bind(new InetSocketAddress(8080));
    // 5 获取selector选择器
    Selector selector = Selector.open();
    // 6 通道注册到选择器，进行监听
    serverSocketChannel.register(selector, SelectionKey.OP_ACCEPT);
    // 7 选择器进行轮询，进行后续操作
    while (selector.select() > 0) {
        Set<SelectionKey> keys = selector.selectedKeys();
        Iterator<SelectionKey> iterator = keys.iterator();
        while (iterator.hasNext()) {
            SelectionKey key = iterator.next();
            if (key.isAcceptable()) {
                System.err.println("accept");
                // 获取连接
                SocketChannel accept = serverSocketChannel.accept();
                // 切换非阻塞
                accept.configureBlocking(false);
                // 注册
                accept.register(selector, SelectionKey.OP_READ);
            } else if (key.isReadable()) {
                SocketChannel channel = (SocketChannel) key.channel();
                ByteBuffer readBuffer = ByteBuffer.allocate(1024);
                //读取数据
                int len = 0;
                while ((len = channel.read(readBuffer)) > 0) {
                    readBuffer.flip();
                    System.err.println(new String(readBuffer.array(), 0, len));
                    readBuffer.clear();
                }
                System.err.println("read");
            }
            iterator.remove();
        }
    }

}

public static void main(String[] args) throws Exception {
    // 绑定 ip port
    SocketChannel socketChannel = SocketChannel.open();
    socketChannel.connect(new InetSocketAddress(8080));
    // 切换非阻塞
    socketChannel.configureBlocking(false);
    // 创建buffer
    ByteBuffer buffer = ByteBuffer.allocate(1024);
    // 写入buffer数据
    Scanner scanner = new Scanner(System.in);
    while (scanner.hasNext()) {
        String txt = scanner.next();
        System.out.println(txt);
        buffer.put(txt.getBytes(StandardCharsets.UTF_8));
        // 模式切换
        buffer.flip();
        // 写入通道
        socketChannel.write(buffer);
        // 清空 关闭
        buffer.clear();
    }
}