Netty 3.9客户端未发送编码器

Question

I'm having an issue using Netty 3.9, where i have made a client that sends/executes an encoder as soon as it connects to the server. But, it just connects without sending the encoder.

ClientHandler

public final class ClientHandler extends IdleStateAwareChannelUpstreamHandler {

    @Override
    public void channelConnected(ChannelHandlerContext ctx, ChannelStateEvent e) throws Exception {
        Channel channel = ctx.getChannel();
        logger.info("Channel connected: " + channel);
    }
}

ClientPipelineFactory

private final ClientHandler handler = new ClientHandler();

@Override
public ChannelPipeline getPipeline() throws Exception {
    ChannelPipeline pipeline = Channels.pipeline();
    pipeline.addLast("handler", handler);
    pipeline.addLast("encoder", new HandshakeEncoder());
    return pipeline;
}

HandshakeEncoder

public final class HandshakeEncoder extends OneToOneEncoder {

    @Override
    protected Object encode(ChannelHandlerContext ctx, Channel channel, Object msg) throws Exception {
        ChannelBuffer buffer = ChannelBuffers.buffer(1);

        buffer.writeByte(49);
        return buffer;
    }
}

Answer 1

The encoder will only be called when you write something to the Channel. I guess what you want is to extend SimpleChannelUpstreamHandler and use something like:

public final class HandshakeHandler extends SimpleChannelUpstreamHandler {

    @Override
    public void channelConnected(ChannelHandlerContext ctx, ChannelStateEvent e) throws Exception {
        Channel channel = ctx.getChannel();
        ChannelBuffer buffer = ChannelBuffers.buffer(1);
        buffer.writeByte(49);
        channel.write(buffer);
    }
}