Netty的Decoder模块阻塞问题：报错

尝试使用Netty接收TCP传输的消息，但是发现如果对象发送消息频率过高，就会出现Decorder中消息不再读取的情况。

服务端代码如下：

public class Server {
	private static Logger log = Logger.getLogger(Server.class);
	final static int REMOTE_PORT = 17650;
	
	@PostConstruct  
    public void bind() throws InterruptedException {
        EventLoopGroup bossGroup = new NioEventLoopGroup();
        EventLoopGroup workerGroup = new NioEventLoopGroup();
        ServerBootstrap serverBootstrap = new ServerBootstrap();
        try {
            serverBootstrap
                    .group(bossGroup,workerGroup)
                    .channel(NioServerSocketChannel.class)
                    .option(ChannelOption.SO_BACKLOG,100)
                    .childOption(ChannelOption.RCVBUF_ALLOCATOR, new AdaptiveRecvByteBufAllocator(64, 1024, 65536))
                    .handler(new LoggingHandler(LogLevel.INFO))
                    .childHandler(new ChannelInitializer<SocketChannel>() {
                        @Override
                        protected void initChannel(SocketChannel socketChannel) throws Exception {
                            //添加解码
                            socketChannel.pipeline().addLast(new Decoder());
                        }
                    });
            ChannelFuture channelFuture = serverBootstrap.bind(REMOTE_PORT).sync();
            channelFuture.channel().closeFuture().sync();
        } finally {
            bossGroup.shutdownGracefully();
            workerGroup.shutdownGracefully();
        }
    }
    
}

 Decoder解码器摘自《Netty实战一书的例子》，如下：

public class Decoder extends ByteToMessageDecoder {
    @Override
    protected void decode(ChannelHandlerContext channelHandlerContext, ByteBuf in, List<Object> out) throws Exception {
        int messageLength = in.readableBytes();
        if (messageLength>=4){
            out.add(in.readInt());
        }
        //打印日志
        System.out.println(in.isReadable());
        System.out.println("readerIndex:"+in.readerIndex());
        System.out.println("writerIndex:"+in.writerIndex());
        System.out.println("capacity:"+in.capacity());
        System.out.println("refcount:"+in.refCnt());
        System.out.println("isWritable:"+in.isWritable());
    }
}

阻塞时，打印的日志如下：

true
readerIndex:23536
writerIndex:23538
capacity:65536
refcount:1
isWritable:true

打印出上面这条日志以后，就再也收不到客户端发送的消息了