docs: private void handle(SelectionKey key) {
  		// 有客户端接入此服务端
  		if (key.isAcceptable()) {
  			// 获取通道 转化为要处理的类型
  			final ServerSocketChannel server = (ServerSocketChannel) key.channel();
  			SocketChannel socketChannel;
  			try {
  				// 获取连接到此服务器的客户端通道
  				socketChannel = server.accept();
  			} catch (IOException e) {
  				throw new IORuntimeException(e);
  			}
  
  			// SocketChannel通道的可读事件注册到Selector中
  			registerChannel(selector, socketChannel, Operation.READ);
  		}
  
  		// 读事件就绪
  		if (key.isReadable()) {
  			final SocketChannel socketChannel = (SocketChannel) key.channel();
  			read(socketChannel);
  
  			// SocketChannel通道的可写事件注册到Selector中
  			registerChannel(selector, socketChannel, Operation.WRITE);
  		}
  
  		// 写事件就绪
  		if (key.isWritable()) {
  			final SocketChannel socketChannel = (SocketChannel) key.channel();
  			write(socketChannel);
  			// SocketChannel通道的可读事件注册到Selector中
  			registerChannel(selector, socketChannel, Operation.READ);
  		}
  	}