匯入相應的包

<dependency>
      <groupId>io.netty</groupId>
      <artifactId>netty-all</artifactId>
      <version>4.1.28.Final</version>
</dependency>

客戶端

/**
 * 客戶端
 */
public class Client {


    private String host;

    private int port;

    public Client(String host, int port) {
        this.host = host;
        this.port = port;
    }

    //啟動客戶端連線
    public void start() {
        //執行緒組
        EventLoopGroup group = new NioEventLoopGroup();
        try {
            //客戶端啟動類
            Bootstrap bootstrap = new Bootstrap();
            bootstrap.group(group)//加入執行緒組
                    .channel(NioSocketChannel.class)
                    .remoteAddress(new InetSocketAddress(host, port))//設定連線引數
                    .handler(new ClientHandler());//設定客戶端連線的處理器

            //阻塞直到連線完成
            ChannelFuture connect = bootstrap.connect().sync();

            //阻塞直到連線成功關閉
            connect.channel().closeFuture().sync();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                group.shutdownGracefully().sync();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }

    }

    public static void main(String[] args) {
        Client client = new Client("127.0.0.1", 9999);
        client.start();
    }
}
 

客戶端處理器

public class ClientHandler extends SimpleChannelInboundHandler<ByteBuf> {

    //連線成功後，接收服務端響應的資料
    protected void channelRead0(ChannelHandlerContext channelHandlerContext, ByteBuf byteBuf) throws Exception {
        System.out.println("接收到服務端響應的資料......" + byteBuf.toString(CharsetUtil.UTF_8));
    }


    //客戶端連線成功後呼叫的
    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {

        System.out.println("客戶端成功連線，並向服務端傳送資料......");
        ctx.writeAndFlush(Unpooled.copiedBuffer("Hello,Netty!", CharsetUtil.UTF_8));
    }


    //連線失敗後呼叫
    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        System.out.println("客戶端連線失敗");
        cause.printStackTrace();
        //關閉資源
        ctx.close();
    }
}
 

服務端

/**
 * 服務端
 */
public class Server {

    private int port;

    public Server(int port) {
        this.port = port;
    }

    public void start() {

        EventLoopGroup group = new NioEventLoopGroup();
        try {
            ServerBootstrap sb = new ServerBootstrap();
            //服務端共用一個Handler
            final ServerHandler serverHandler = new ServerHandler();

            sb.group(group)
                    .channel(NioServerSocketChannel.class)
                    .localAddress(new InetSocketAddress(port))
                    .childHandler(new ChannelInitializer<SocketChannel>() {
                        /*接收到連線請求，新啟一個socket通訊，也就是channel，每個channel
                         * 有自己的事件的handler*/
                        protected void initChannel(SocketChannel socketChannel) throws Exception {

                            socketChannel.pipeline().addLast(serverHandler);
                        }
                    });

            ChannelFuture sync = sb.bind().sync();

            sync.channel().closeFuture().sync();
        } catch (Exception e) {
            e.printStackTrace();
        }finally {
            try {
                group.shutdownGracefully().sync();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }

    }


    public static void main(String[] args) {
        new Server(9999).start();
    }
}
 

服務端處理器

/*指明我這個handler可以在多個channel之間共享，意味這個實現必須執行緒安全的。*/
@ChannelHandler.Sharable
public class ServerHandler extends ChannelInboundHandlerAdapter {

    //服務端讀取完客戶端的所有資料後
    @Override
    public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
        ctx.writeAndFlush(Unpooled.EMPTY_BUFFER)/*flush掉所有的資料*/
                .addListener(ChannelFutureListener.CLOSE);/*當flush完成後，關閉連線*/
    }


    //服務端讀取客戶端的資料
    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
        ByteBuf msg1 = (ByteBuf) msg;
        System.out.println("服務端接收到客戶端的資料......." + msg1.toString(CharsetUtil.UTF_8));
        ctx.write(msg1);
    }


    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        cause.printStackTrace();
        ctx.close();
    }
}

執行結果：

服務端：

客戶端：