client 关闭后会执行 finally 代码块，可以在这里可以进行重连操作

public class NettyClient implements Runnable {    private final String host;    private final int port;    private final int reconnectSleepSeconds;    public NettyClient(String host, int port, int reconnectSleepSeconds){        this.host = host;        this.port = port;        this.reconnectSleepSeconds = reconnectSleepSeconds;    }    @Override    public void run() {        connect();    }    private void connect(){        EventLoopGroup workerGroup = new NioEventLoopGroup();        try {            Bootstrap b = new Bootstrap();            b.group(workerGroup);            b.channel(NioSocketChannel.class);            b.option(ChannelOption.SO_KEEPALIVE, true);            b.handler(new ChannelInitializer
    
     () {                @Override                public void initChannel(SocketChannel ch) throws Exception {                    // TODO: 添加 Handler                }            });            ChannelFuture f = b.connect(host, port).sync();            f.channel().closeFuture().sync();        } catch (Exception e){            e.printStackTrace();        } finally {            workerGroup.shutdownGracefully();            try {                TimeUnit.SECONDS.sleep(reconnectSleepSeconds);                connect(); // 断线重连            } catch (InterruptedException e) {                e.printStackTrace();            }        }    }}
    

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