Java : Netty 入门案例

接收端代码:

public class IOServer {
    public static void main(String[] args) throws IOException, InterruptedException {
        ServerBootstrap serverBootstrap = new ServerBootstrap();
        NioEventLoopGroup boos = new NioEventLoopGroup();
        NioEventLoopGroup worker = new NioEventLoopGroup();
        serverBootstrap
                .group(boos, worker)
                .channel(NioServerSocketChannel.class)
                .childHandler(new ChannelInitializer<NioSocketChannel>() {
                    protected void initChannel(NioSocketChannel ch) {
                        ch.pipeline().addLast(new StringDecoder());
                        ch.pipeline().addLast(new SimpleChannelInboundHandler<String>() {
                            @Override
                            protected void channelRead0(ChannelHandlerContext ctx, String msg) throws Exception {
                                System.out.println(msg);
                            }
                        });
                    }
                })
                .bind(9990);
    }
}

发送端代码:

public class IOClient {
    public static void main(String[] args) throws InterruptedException {
        Bootstrap bootstrap = new Bootstrap();
        NioEventLoopGroup group = new NioEventLoopGroup();
        bootstrap.group(group)
                .channel(NioSocketChannel.class)
                .handler(new ChannelInitializer<Channel>() {
                    @Override
                    protected void initChannel(Channel ch) throws Exception {
                        ch.pipeline().addLast(new StringEncoder());
                    }
                });
        Channel channel = bootstrap.connect("127.0.0.1", 9999).channel();
        while (true) {
            channel.writeAndFlush(new Date() + "hello world");
            Thread.sleep(2000);
        }
    }
}

此案例基于netty4, 并且推荐使用netty4进行开发, netty5分支已经被作者remove, 原因: https://github.com/netty/netty/issues/4466

netty4用 ChannelInboundHandlerAdapter 和 ChannelOutboundHandlerAdapter 来区分上行(接收)和下行(发送)的数据, 而 netty5中这两个类均已经被废弃