CloseFuture

@Slf4j
public class CloseFutureClient {
    public static void main(String[] args) throws InterruptedException {
        NioEventLoopGroup group new NioEventLoopGroup();
        ChannelFuture channelFuture = new Bootstrap()
                .group(group)
                .channel(NioSocketChannel.class)
                .handler(new ChannelInitializer<NioSocketChannel>() {
                    @Override // 在连接建立后被调用
                    protected void initChannel(NioSocketChannel ch) throws Exception {
                        ch.pipeline().addLast(new LoggingHandler(LogLevel.DEBUG));
                        ch.pipeline().addLast(new StringEncoder());
                    }
                })
                .connect(new InetSocketAddress("localhost", 8080));
        Channel channel = channelFuture.sync().channel();
        log.debug("{}", channel);
        new Thread(()->{
            Scanner scanner = new Scanner(System.in);
            while (true) {
                String line = scanner.nextLine();
                if ("q".equals(line)) {
                    channel.close(); // close 异步操作 1s 之后
//                    log.debug("处理关闭之后的操作"); // 不能在这里善后
                    break;
                }
                channel.writeAndFlush(line);
            }
        }, "input").start();
        // 获取 CloseFuture 对象， 1) 同步处理关闭， 2) 异步处理关闭
        ChannelFuture closeFuture = channel.closeFuture();
        /*log.debug("waiting close...");
        closeFuture.sync();
        log.debug("处理关闭之后的操作");*/
        closeFuture.addListener(new ChannelFutureListener() {
            @Override
            public void operationComplete(ChannelFuture future) throws Exception {
                log.debug("处理关闭之后的操作");
                group.shutdownGracefully();
            }
        });
    }
}