public class Server {

    public static void main(String[] args) throws Exception {

        //1 创建线两个程组

        //一个是用于处理服务器端接收客户端连接的

        //一个是进行网络通信的（网络读写的）

        EventLoopGroup pGroup = new NioEventLoopGroup();

        EventLoopGroup cGroup = new NioEventLoopGroup();

        //2 创建辅助工具类，用于服务器通道的一系列配置

        ServerBootstrap b = new ServerBootstrap();

        b.group(pGroup, cGroup)        //绑定俩个线程组

        .channel(NioServerSocketChannel.class)        //指定NIO的模式

        .option(ChannelOption.SO_BACKLOG, 1024)        //设置tcp缓冲区

        .option(ChannelOption.SO_SNDBUF, 32*1024)    //设置发送缓冲大小

        .option(ChannelOption.SO_RCVBUF, 32*1024)    //这是接收缓冲大小

        .option(ChannelOption.SO_KEEPALIVE, true)    //保持连接

        .childHandler(new ChannelInitializer<SocketChannel>() {

            @Override

            protected void initChannel(SocketChannel sc) throws Exception {

                //3 在这里配置具体数据接收方法的处理

                sc.pipeline().addLast(new ServerHandler());

            }

        });

        //4 进行绑定

        ChannelFuture cf1 = b.bind(8765).sync();

        //ChannelFuture cf2 = b.bind(8764).sync();

        //5 等待关闭

        cf1.channel().closeFuture().sync();

        //cf2.channel().closeFuture().sync();

        pGroup.shutdownGracefully();

        cGroup.shutdownGracefully();

    }

}

public class ServerHandler extends ChannelHandlerAdapter {

    @Override

    public void channelActive(ChannelHandlerContext ctx) throws Exception {

        System.out.println("server channel active... ");

    }

    @Override

    public void channelRead(ChannelHandlerContext ctx, Object msg)

            throws Exception {

            ByteBuf buf = (ByteBuf) msg;

            byte[] req = new byte[buf.readableBytes()];

            buf.readBytes(req);

            String body = new String(req, "utf-8");

            System.out.println("Server :" + body );

            String response = "进行返回给客户端的响应：" + body ;

            ctx.writeAndFlush(Unpooled.copiedBuffer(response.getBytes()));

            //.addListener(ChannelFutureListener.CLOSE);//会自动关闭连接

    }

    @Override

    public void channelReadComplete(ChannelHandlerContext ctx)

            throws Exception {

        System.out.println("读完了");

        ctx.flush();

    }

    @Override

    public void exceptionCaught(ChannelHandlerContext ctx, Throwable t)

            throws Exception {

        ctx.close();

    }

}

public class Client {

    public static void main(String[] args) throws Exception{

        EventLoopGroup group = new NioEventLoopGroup();

        Bootstrap b = new Bootstrap();

        b.group(group)

        .channel(NioSocketChannel.class)

        .handler(new ChannelInitializer<SocketChannel>() {

            @Override

            protected void initChannel(SocketChannel sc) throws Exception {

                sc.pipeline().addLast(new ClientHandler());

            }

        });

        ChannelFuture cf1 = b.connect("127.0.0.1", 8765).sync();

        //ChannelFuture cf2 = b.connect("127.0.0.1", 8764).sync();

        //发送消息

        Thread.sleep(1000);

        cf1.channel().writeAndFlush(Unpooled.copiedBuffer("777".getBytes()));

        cf1.channel().writeAndFlush(Unpooled.copiedBuffer("666".getBytes()));

        //cf2.channel().writeAndFlush(Unpooled.copiedBuffer("888".getBytes()));

        Thread.sleep(2000);

        cf1.channel().writeAndFlush(Unpooled.copiedBuffer("888".getBytes()));

        //cf2.channel().writeAndFlush(Unpooled.copiedBuffer("666".getBytes()));

        cf1.channel().closeFuture().sync();

        //cf2.channel().closeFuture().sync();

        group.shutdownGracefully();

    }

}

public class ClientHandler extends ChannelHandlerAdapter{

    @Override

    public void channelActive(ChannelHandlerContext ctx) throws Exception {

    }

    @Override

    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {

        try {

            ByteBuf buf = (ByteBuf) msg;

            byte[] req = new byte[buf.readableBytes()];

            buf.readBytes(req);

            String body = new String(req, "utf-8");

            System.out.println("Client :" + body );

            String response = "收到服务器端的返回信息：" + body;

        } finally {

            ReferenceCountUtil.release(msg);

        }

    }

    @Override

    public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {

    }

    @Override

    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause)

            throws Exception {

        ctx.close();

    }

}