netty telnet 应用实例server代码

public class TelnetServer {

    public static void main(String[] args) throws Exception {
        // Configure the server.
        ServerBootstrap bootstrap = new ServerBootstrap(
                new NioServerSocketChannelFactory(
                        Executors.newCachedThreadPool(),
                        Executors.newCachedThreadPool()));

        // Configure the pipeline factory.
        bootstrap.setPipelineFactory(new TelnetServerPipelineFactory());

        // Bind and start to accept incoming connections.
        bootstrap.bind(new InetSocketAddress(8080));
    }
}

public class TelnetServerPipelineFactory implements
        ChannelPipelineFactory {

    public ChannelPipeline getPipeline() throws Exception {
        // Create a default pipeline implementation.
        ChannelPipeline pipeline = pipeline();

        // Add the text line codec combination first,
        pipeline.addLast("framer", new DelimiterBasedFrameDecoder(
                8192, Delimiters.lineDelimiter()));
        pipeline.addLast("decoder", new StringDecoder());
        pipeline.addLast("encoder", new StringEncoder());

        // and then business logic.
        pipeline.addLast("handler", new TelnetServerHandler());

        return pipeline;
    }
}

public class TelnetServerHandler extends SimpleChannelUpstreamHandler {

    private static final Logger logger = Logger.getLogger(
            TelnetServerHandler.class.getName());

    @Override
    public void handleUpstream(
            ChannelHandlerContext ctx, ChannelEvent e) throws Exception {
        if (e instanceof ChannelStateEvent) {
            logger.info(e.toString());
        }
        super.handleUpstream(ctx, e);
    }

    @Override
    public void channelConnected(
            ChannelHandlerContext ctx, ChannelStateEvent e) throws Exception {
        // Send greeting for a new connection.
        e.getChannel().write(
                "Welcome to " + InetAddress.getLocalHost().getHostName() + "!\r\n");
        e.getChannel().write("It is " + new Date() + " now.\r\n");
    }

    @Override
    public void messageReceived(
            ChannelHandlerContext ctx, MessageEvent e) {

        // Cast to a String first.
        // We know it is a String because we put some codec in TelnetPipelineFactory.
        String request = (String) e.getMessage();

        // Generate and write a response.
        String response;
        boolean close = false;
        if (request.length() == 0) {
            response = "Please type something.\r\n";
        } else if (request.toLowerCase().equals("bye")) {
            response = "Have a good day!\r\n";
            close = true;
        } else {
            response = "Did you say '" + request + "'?\r\n";
        }

        // We do not need to write a ChannelBuffer here.
        // We know the encoder inserted at TelnetPipelineFactory will do the conversion.
        ChannelFuture future = e.getChannel().write(response);

        // Close the connection after sending 'Have a good day!'
        // if the client has sent 'bye'.
        if (close) {
            future.addListener(ChannelFutureListener.CLOSE);
        }
    }

    @Override
    public void exceptionCaught(
            ChannelHandlerContext ctx, ExceptionEvent e) {
        logger.log(
                Level.WARNING,
                "Unexpected exception from downstream.",
                e.getCause());
        e.getChannel().close();
    }
}