Question

我们有一个用c＃编写的套接字客户端程序，我试图用Netty重写它。 c＃登录方法如下所示：

public bool login(String prefix, string username, string password)
    {
        Send(String.Format("{0}{1},{2}\n", prefix, username, password));

        try
        {
            var _4B = new byte[4];
            _socket.Receive(_4B, 4, SocketFlags.None);
            var len = ConvertToInteger(_4B);
            var b = new byte[len];
            _socket.Receive(b, len, SocketFlags.None);
            GZipStream stream = new GZipStream(new MemoryStream(b, 0, len), CompressionMode.Decompress);
            StreamReader sr = new StreamReader(stream, Encoding.GetEncoding("GBK"));
            String line = sr.ReadToEnd();
            Window.MSG("Socket", "Feed login: " + line, MessageType.SystemMessage);
        }
        catch (SocketException e)
        {
            Window.MSG("Socket", "Socket Exception: " + e.Message, MessageType.Error);
            return false;
        }
        return true;
    }

上面的代码工作正常，然后我写了一个如下的Netty客户端：

public void start() throws Exception {
    EventLoopGroup group = new NioEventLoopGroup();
    try {
        Bootstrap bootstrap = new Bootstrap();
        bootstrap.group(group).channel(NioSocketChannel.class)
                .remoteAddress(new InetSocketAddress(host, port))
                .handler(new ChannelInitializer<SocketChannel>() {
                    @Override
                    public void initChannel(SocketChannel ch)
                            throws Exception {
                        ChannelPipeline pipeline = ch.pipeline();
                        pipeline.addLast("lengthFieldBasedFrameDecoder",
                                new LengthFieldBasedFrameDecoder(
                                        Integer.MAX_VALUE, 0, 4, 0, 4));
                        /*
                        pipeline.addLast("gzipdeflater", ZlibCodecFactory
                                .newZlibDecoder(ZlibWrapper.GZIP)); */

                        pipeline.addLast("decoder", new StringDecoder(
                                Charset.forName("gbk")));
                        pipeline.addLast("encoder", new StringEncoder());
                        pipeline.addLast("handler", new FeedClientHandler());

                    }
                });
        ChannelFuture future = bootstrap.connect().sync();
        future.channel().writeAndFlush(login);
        Thread.sleep(600000); // todo
    } finally {
        group.shutdownGracefully();
    }
}

这个netty客户端无法正常工作，并且无法获得任何输出，我调试并发现LengthFieldBasedFrameDecoder.decode（ChannelHandlerContext ctx，ByteBuf in）方法返回null，因为in.readableBytes＆lt; frameLengthInt（in.readableBytes = 1028，frameLengthInt = 1882716544）。

我不知道如何让它工作，有什么建议吗？提前谢谢：）

Answer 1

感谢trustin和Suvitruf的评论，在将LengthFieldBasedFrameDecoder的ByteOrder设置为LITTLE_ENDIAN后，客户端正常工作！

pipeline.addLast("lengthFieldBasedFrameDecoder", new LengthFieldBasedFrameDecoder(ByteOrder.LITTLE_ENDIAN, Integer.MAX_VALUE, 0, 4, 0, 4, true));

Netty 4.0 LengthFieldBasedFrameDecoder不工作

1 个答案: