netty server:

public class NettyServer {
    public static void main(String[] args) {
        EventLoopGroup bossGroup=new NioEventLoopGroup(1);//处理连接请求
        EventLoopGroup workerGroup=new NioEventLoopGroup();//默认线程数量为cpu核数的两倍，处理业务
        try {
            ServerBootstrap bootstrap=new ServerBootstrap();//创建服务器端的启动对象
            bootstrap.group(bossGroup,workerGroup)
                    .channel(NioServerSocketChannel.class)
                    .option(ChannelOption.SO_BACKLOG,1024)
                    .childHandler(new ChannelInitializer<SocketChannel>() {
                        protected void initChannel(SocketChannel socketChannel) {
                            socketChannel.pipeline().addLast(new NettyServerHandler());
                        }
                    });
            System.out.println("netty server start");
            //启动服务器绑定端口，bind是异步操作，sync是等待
            ChannelFuture cf=bootstrap.bind(9000).sync();

            cf.channel().closeFuture().sync();
            System.out.println("******************server close");
        }catch (Exception e){
            e.printStackTrace();
        }
    }
}

NettyServerHandler:

public class NettyServerHandler extends ChannelInboundHandlerAdapter {
    /**
     * 读取客户端的数据
     * @param ctx
     * @param msg
     * @throws Exception
     */
    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
        System.out.println("server 读取数据线程"+Thread.currentThread().getName());

        ByteBuf byteBuf= (ByteBuf) msg;
        System.out.println("收到客户端发送的消息："+byteBuf.toString(CharsetUtil.UTF_8));
    }

    /**
     * 数据读取完毕处理方法
     * @param ctx
     * @throws Exception
     */
    @Override
    public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
        ByteBuf byteBuf= Unpooled.copiedBuffer("Hello Client".getBytes(CharsetUtil.UTF_8));
        ctx.writeAndFlush(byteBuf);
    }

    /**
     * 处理异常一般是关闭通道
     * @param ctx
     * @param cause
     * @throws Exception
     */
    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        ctx.close();
    }
}

NettyClient

public class NettyClient {
    public static void main(String[] args) throws InterruptedException {
        EventLoopGroup group=new NioEventLoopGroup();
        try {
            Bootstrap bootstrap=new Bootstrap();
            bootstrap.group(group)
                    .channel(NioSocketChannel.class)
                    .handler(new ChannelInitializer<SocketChannel>() {
                        protected void initChannel(SocketChannel socketChannel) {
                            socketChannel.pipeline().addLast(new NettyClientHandler());//
                        }
                    });
            System.out.println("netty client start");
            //启动客户端连接服务器
            ChannelFuture cf =bootstrap.connect("127.0.0.1",9000).sync();
            //关闭通道进行监听
            cf.channel().closeFuture().sync();
            System.out.println("********************client close");
        } finally {
            group.shutdownGracefully();
        }
    }
}

NettyClientHandler

public class NettyClientHandler  extends ChannelInboundHandlerAdapter {

    /**
     * 当客户端连接到服务端是触发
     * @param ctx
     * @throws Exception
     */
    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        ByteBuf byteBuf= Unpooled.copiedBuffer("Hello Server".getBytes(CharsetUtil.UTF_8));
        ctx.writeAndFlush(byteBuf);
    }

    /**
     * 读取服务端发送的数据
     * @param ctx
     * @param msg
     * @throws Exception
     */
    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
        ByteBuf byteBuf= (ByteBuf) msg;
        System.out.println("收到服务端发送的消息："+byteBuf.toString(CharsetUtil.UTF_8));
        System.out.println("服务端的地址："+ctx.channel().remoteAddress());
    }

    /**
     * 处理异常一般是关闭通道
     * @param ctx
     * @param cause
     * @throws Exception
     */
    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        ctx.close();
    }
}