关于netty的简单实现

1. 新建两个maven项目, 分别为

netty-server: netty的服务端: 消息的消费者

netty-client: netty的客户端: 消息的生产者

2. 分别引入netty的maven依赖

<dependency>
    <groupId>io.netty</groupId>
    <artifactId>netty-all</artifactId>
    <version>4.1.6.Final</version>
</dependency>

3. netty-server服务端

  3.1. 服务端引导类

public class EchoServer {

    private int port;

    private EchoServer(int port) {
        this.port = port;
    }

    private void start() throws Exception {
        System.out.println("Echo Server Start");
        EventLoopGroup group = new NioEventLoopGroup();
        try {
            ServerBootstrap b = new ServerBootstrap();
            b.group(group)
                    .channel(NioServerSocketChannel.class)
                    .localAddress(new InetSocketAddress(port))
                    .childHandler(new ChannelInitializer<SocketChannel>() {
                        @Override
                        public void initChannel(SocketChannel ch) throws Exception {
                            ch.pipeline().addLast(new EchoServerHandler());
                        }
                    });
            ChannelFuture f = b.bind().sync();
            System.out.println("Server Start Listen At: " + port);
            f.channel().closeFuture().sync();
        } finally {
            group.shutdownGracefully();
        }
    }

    public static void main(String[] args) throws Exception {
        int port;
        if (args.length > 0) {
            port = Integer.parseInt(args[0]);
        } else {
            port = 8080;
        }
        new EchoServer(port).start();
    }
}

  3.2. 服务端消息消费业务

public class EchoServerHandler extends ChannelInboundHandlerAdapter {

    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) {
        ByteBuf bb = (ByteBuf) msg;
        bb.markReaderIndex();
        System.out.println("Server Received: " + ByteBufUtil.hexDump(bb.readBytes(bb.readableBytes())));
        bb.resetReaderIndex();
        ctx.write(msg);
    }

    @Override
    public void channelReadComplete(ChannelHandlerContext ctx) {
        ctx.writeAndFlush(Unpooled.EMPTY_BUFFER).addListener(ChannelFutureListener.CLOSE);
    }

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

4. netty-client客户端

  4.1. 客户端引导类

public class EchoClient {
    private String host;
    private int port;

    private EchoClient(String host, int port) {
        this.host = host;
        this.port = port;
    }

    private void start() throws Exception {
        System.out.println("Echo Client Start");
        EventLoopGroup group = new NioEventLoopGroup();
        try {
            Bootstrap b = new Bootstrap();
            b.group(group)
                    .channel(NioSocketChannel.class)
                    .remoteAddress(new InetSocketAddress(host, port))
                    .handler(new ChannelInitializer<SocketChannel>() {
                        @Override
                        public void initChannel(SocketChannel ch) throws Exception {
                            ch.pipeline().addLast(new EchoClientHandler());
                        }
                    });

            ChannelFuture f = b.connect().sync();
            System.out.println("Server Client Listen Host: [" + host + "] And Port: [" + port + "]");
            f.channel().closeFuture().sync();
        } finally {
            group.shutdownGracefully();
        }
    }

    public static void main(String[] args) throws Exception {
        String host = "127.0.0.1";
        int port = 8080;
        int len = 2;
        if (args.length == len) {
            host = args[0];
            port = Integer.parseInt(args[1]);
        }

        new EchoClient(host, port).start();
    }

}

  4.2 客户端消息生产业务

public class EchoClientHandler extends SimpleChannelInboundHandler<ByteBuf> {

    @Override
    public void channelActive(ChannelHandlerContext ctx) {
        ctx.writeAndFlush(Unpooled.copiedBuffer("Netty Rocks!", CharsetUtil.UTF_8));
    }

    @Override
    public void channelRead0(ChannelHandlerContext ctx, ByteBuf in) {
        System.out.println("Client Received: " + ByteBufUtil.hexDump(in.readBytes(in.readableBytes())));
    }

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

5. 测试:

  5.1. 启动服务端

  5.2. 启动客户端

  5.3. 再看服务端