netty例子-客户端每隔5秒发送查询时间的请求，服务器端响应请求

netty是jboss公司开发的，基于异步的、事件驱动的网络应用程序框架，快速开发高性能、高可靠性的服务器和客户端程序

public class TimeServer {
    private int port=8080;
    public void run() throws Exception {
        EventLoopGroup bossGroup = new NioEventLoopGroup(); // (1)
        EventLoopGroup workerGroup = new NioEventLoopGroup();
        try {
            ServerBootstrap b = new ServerBootstrap(); // (2)
            b.group(bossGroup, workerGroup)
                    .channel(NioServerSocketChannel.class) // (3)
                    .childHandler(new ChannelInitializer<SocketChannel>() { // (4)
                        @Override
                        public void initChannel(SocketChannel ch) throws Exception {
                            ch.pipeline().addLast(new LineBasedFrameDecoder(1024));
                            ch.pipeline().addLast(new StringDecoder());
                            ch.pipeline().addLast(new TimeServerHandler());
                        }
                    });
            ChannelFuture f = b.bind(port).sync(); // (5)
            System.out.println("TimeServer Started on 8080...");
            f.channel().closeFuture().sync();
        } finally {
            workerGroup.shutdownGracefully();
            bossGroup.shutdownGracefully();
        }
    }
    public static void main(String[] args) throws Exception {
        new TimeServer().run();
    }
}

public class TimeServerHandler extends ChannelInboundHandlerAdapter {
   @Override
   public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception { // 1
      String request = (String) msg; //2
      String response = null;
      if ("QUERY TIME ORDER".equals(request)) { // 3
         response = new Date(System.currentTimeMillis()).toString();
      } else {
         response = "BAD REQUEST";
      }
      response = response + System.getProperty("line.separator"); // 4
      ByteBuf resp = Unpooled.copiedBuffer(response.getBytes()); // 5
      ctx.writeAndFlush(resp); // 6
   }
}

public class TimeClient {
    public static void main(String[] args) throws Exception {
        String host = "localhost";
        int port = 8080;
        EventLoopGroup workerGroup = new NioEventLoopGroup();
        try {
            Bootstrap b = new Bootstrap(); // (1)
            b.group(workerGroup); // (2)
            b.channel(NioSocketChannel.class); // (3)
            b.handler(new ChannelInitializer<SocketChannel>() {// (4)
                @Override
                public void initChannel(SocketChannel ch) throws Exception {
                    ch.pipeline().addLast(new LineBasedFrameDecoder(1024));
                    ch.pipeline().addLast(new StringDecoder());
                    ch.pipeline().addLast(new TimeClientHandler());
                }
            });
            // Start the client.
            ChannelFuture f = b.connect(host, port).sync(); // (5)
            // Wait until the connection is closed.
            f.channel().closeFuture().sync();
        } finally {
            workerGroup.shutdownGracefully();
        }
    }
}

public class TimeClientHandler extends ChannelInboundHandlerAdapter {
    private byte[] req = ("QUERY TIME ORDER" + System.getProperty("line.separator")).getBytes();

    @Override
    public void channelActive(ChannelHandlerContext ctx) throws InterruptedException {// 1
        sendMsg(ctx);
    }

    public void sendMsg(ChannelHandlerContext ctx) {
        Executors.newSingleThreadExecutor().submit(new MsgRunnable(ctx));
    }

    class MsgRunnable implements Runnable {
        ChannelHandlerContext ctx;

        MsgRunnable(ChannelHandlerContext ctx) {
            this.ctx = ctx;
        }

        @Override
        public void run() {
            while (true) {
                ByteBuf message = Unpooled.buffer(req.length);
                message.writeBytes(req);
                ctx.writeAndFlush(message);
                try {
                    Thread.sleep(5000);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }

            }

        }
    }

    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
        String body = (String) msg;
        System.out.println("Now is:" + body);
    }
}