NIO テクノロジーは Java 関数にどのように実装されますか?

// 服务器端
ServerSocketChannel serverSocketChannel = ServerSocketChannel.open();
serverSocketChannel.bind(new InetSocketAddress(PORT));
while (true) {
  SocketChannel socketChannel = serverSocketChannel.accept();
  ... // 处理请求
}

// 客户端
SocketChannel socketChannel = SocketChannel.open();
socketChannel.connect(new InetSocketAddress(HOST, PORT));
... // 发送请求

// 初始化 selector
Selector selector = Selector.open();

// 注册服务器端 channel 到 selector
serverSocketChannel.register(selector, SelectionKey.OP_ACCEPT);

// 循环监听事件
while (true) {
  // 阻塞直到一个或多个通道就绪
  int readyChannels = selector.select();

  if (readyChannels > 0) {
    Set<SelectionKey> selectedKeys = selector.selectedKeys();

    for (SelectionKey key : selectedKeys) {
      if (key.isAcceptable()) {
        // 处理传入连接
      } else if (key.isReadable()) {
        // 处理可读数据
      } else if (key.isWritable()) {
        // 处理可写数据
      }
    }
    selectedKeys.clear();
  }
}