异步的、事件驱动的网络应用程序框架和工具Netty

Hello World in Netty

    1、HelloWorldServer

     ServerBootstrap bootstrap = new ServerBootstrap(new
        NioServerSocketChannelFactory(
        Executors.newCachedThreadPool(),
        Executors.newCachedThreadPool()));

     bootstrap.setPipelineFactory(new ChannelPipelineFactory() {
        public ChannelPipeline getPipeline()       {
          ChannelPipeline pipeline = Channels.pipeline();
          pipeline.addLast("decoder", new StringDecoder());
          pipeline.addLast("encoder", new StringEncoder());
          pipeline.addLast("handler", new HelloWorldServerHandler());
          return pipeline;
        }
     });

     bootstrap.bind(new InetSocketAddress(8080));

    HelloWorldServerHandler

     public void channelConnected(ChannelHandlerContext ctx,
       ChannelStateEvent e) throws Exception {
       e.getChannel().write("Hello, World");
     }

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

 2、HelloWorldClient
       ClientBootstrap bootstrap = new ClientBootstrap(new NioClientSocketChannelFactory(
       Executors.newCachedThreadPool(), Executors.newCachedThreadPool()));

       bootstrap.setPipelineFactory(new ChannelPipelineFactory() {
            public ChannelPipeline getPipeline() {
              ChannelPipeline pipeline = pipeline();
              pipeline.addLast("decoder", new StringDecoder());
              pipeline.addLast("encoder", new StringEncoder());
              pipeline.addLast("handler", new HelloWorldClientHandler());
              return pipeline;
            }
       });

       ChannelFuture future = bootstrap.connect(new InetSocketAddress("localhost", 8080));

       future.getChannel().getCloseFuture().awaitUninterruptibly();

       bootstrap.releaseExternalResources();

    HelloWorldClientHandler

     public void messageReceived(ChannelHandlerContext ctx,
        MessageEvent e) {
         String message = (String) e.getMessage();
         System.out.println(message);
         e.getChannel().close();

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

     }