netty 底层的工作原理

什么是 Netty

Netty 是一个高性能的网络通信框架，封装了底层复杂的 socket 编程细节，让我们可以高效快速构建自己的应用

有哪些开源框架用了 Netty 呢？grpc、dubbo、kafka、rocketmq、zookeeper、hadoop

Netty Demo

server 端启动 netty 服务器

public static void main(String[] args) throws InterruptedException {
    EventLoopGroup boss = new NioEventLoopGroup();
    EventLoopGroup worker = new NioEventLoopGroup();
    try {
        ServerBootstrap serverBootstrap = new ServerBootstrap();
        serverBootstrap.group(boss, worker)
                .channel(NioServerSocketChannel.class)
                // 设置接收缓冲区大小
          			// 控制窗口值
                .childOption(ChannelOption.SO_RCVBUF, 32 * 1024)
                // 设置发送缓冲区大小
                .childOption(ChannelOption.SO_SNDBUF, 32 * 1023)
                .childHandler(new ChannelInitializer() {
                    @Override
                    protected void initChannel(SocketChannel ch) throws Exception {
                        ChannelPipeline channelPipeline = ch.pipeline();
                        channelPipeline.addLast(new JdrpcCodec());
                        channelPipeline.addLast(new JdrpcServerHandler());
                    }
                });
        ChannelFuture channelFuture = serverBootstrap.bind(JdrpcConstant.PORT).sync();

        channelFuture.addListener(future -> {
           if (future.isSuccess()) {
               logger.info("服务启动成功，绑定端口: {}", JdrpcConstant.PORT);
           } else {
               logger.error("服务启动失败");
           }
        });
        channelFuture.channel().closeFuture().sync();

    } finally {
        boss.shutdownGracefully();
        worker.shutdownGracefully();
    }
}

启动 client

public static void main(String[] args) throws InterruptedException {
    EventLoopGroup eventLoopGroup = new NioEventLoopGroup();
    Bootstrap bootstrap = new Bootstrap();
    bootstrap.group(eventLoopGroup)
            .channel(NioSocketChannel.class)
      			// 连接超时时间
            .option(ChannelOption.CONNECT_TIMEOUT_MILLIS, 5000)
            // 保持长连接心跳
            .option(ChannelOption.SO_KEEPALIVE, true)
            // 禁用 Nagle 算法
            .option(ChannelOption.TCP_NODELAY, true)
            .handler(new ChannelInitializer() {
                @Override
                protected void initChannel(SocketChannel ch) throws Exception {
                    ch.pipeline()
                      			// 设置编码解码器
                            .addLast(new JdrpcCodec())
                            // 业务逻辑处理类
                            .addLast(new JdrpcClientHandler());
                }
            });
    bootstrap.connect("127.0.0.1", JdrpcConstant.PORT).addListener(future -> {
        if (future.isSuccess()) {
            logger.info("