client

/**
 * initialize and close Bootstrap object
 *
 * @author shuang.kou
 * @createTime 2020年05月29日 17:51:00
 */
@Slf4j
public final class NettyRpcClient implements RpcRequestTransport {

    private final Bootstrap bootstrap;
    private final EventLoopGroup eventLoopGroup;

    public NettyRpcClient() {

        eventLoopGroup = new NioEventLoopGroup();
        bootstrap = new Bootstrap();
        bootstrap.group(eventLoopGroup)
                .channel(NioSocketChannel.class)
                .handler(new LoggingHandler(LogLevel.INFO))   //以下为可变
                .option(ChannelOption.CONNECT_TIMEOUT_MILLIS, 5000) //以下为可变
                .handler(new ChannelInitializer<SocketChannel>() {
                    @Override
                    protected void initChannel(SocketChannel ch) {
                        ChannelPipeline p = ch.pipeline();
						//以下为可变
                        p.addLast(new IdleStateHandler(0, 5, 0, TimeUnit.SECONDS)); 
                        p.addLast(new RpcMessageEncoder());
                        p.addLast(new RpcMessageDecoder());
                        p.addLast(new NettyRpcClientHandler());
                    }
                });
    }

    //连接并获得通道
    @SneakyThrows
    public Channel doConnect(InetSocketAddress inetSocketAddress) {
        CompletableFuture<Channel> completableFuture = new CompletableFuture<>();
        bootstrap.connect(inetSocketAddress).addListener((ChannelFutureListener) future -> {
            if (future.isSuccess()) {
                log.info("The client has connected [{}] successful!", inetSocketAddress.toString());
                completableFuture.complete(future.channel());
            } else {
                throw new IllegalStateException();
            }
        });
        return completableFuture.get();
    }

    //优雅关闭
    public void close() {
        eventLoopGroup.shutdownGracefully();
    }
}

server

@Slf4j
@Component
public class NettyRpcServer {

    public static final int PORT = 9998;

    @SneakyThrows
    public void start() {
  
        String host = InetAddress.getLocalHost().getHostAddress();
        EventLoopGroup bossGroup = new NioEventLoopGroup(1);
        EventLoopGroup workerGroup = new NioEventLoopGroup();
        DefaultEventExecutorGroup serviceHandlerGroup = new DefaultEventExecutorGroup(
                RuntimeUtil.cpus() * 2,
                ThreadPoolFactoryUtil.createThreadFactory("service-handler-group", false)
        );
        try {
            ServerBootstrap b = new ServerBootstrap();
            b.group(bossGroup, workerGroup)
                    .channel(NioServerSocketChannel.class)
                    // TCP默认开启了 Nagle 算法，该算法的作用是尽可能的发送大数据快，减少网络传输。TCP_NODELAY 参数的作用就是控制是否启用 Nagle 算法。
                    .childOption(ChannelOption.TCP_NODELAY, true)
                    // 是否开启 TCP 底层心跳机制
                    .childOption(ChannelOption.SO_KEEPALIVE, true)
                    //表示系统用于临时存放已完成三次握手的请求的队列的最大长度,如果连接建立频繁，服务器处理创建新连接较慢，可以适当调大这个参数
                    .option(ChannelOption.SO_BACKLOG, 128)
                    .handler(new LoggingHandler(LogLevel.INFO))
                    // 当客户端第一次进行请求的时候才会进行初始化
                    .childHandler(new ChannelInitializer<SocketChannel>() {
                        @Override
                        protected void initChannel(SocketChannel ch) {
                            // 30 秒之内没有收到客户端请求的话就关闭连接
                            ChannelPipeline p = ch.pipeline();
                            p.addLast(new IdleStateHandler(30, 0, 0, TimeUnit.SECONDS));
                            p.addLast(new RpcMessageEncoder());
                            p.addLast(new RpcMessageDecoder());
                            p.addLast(serviceHandlerGroup, new NettyRpcServerHandler());
                        }
                    });

            // 绑定端口，同步等待绑定成功
            ChannelFuture f = b.bind(host, PORT).sync();
            // 等待服务端监听端口关闭
            f.channel().closeFuture().sync();
        } catch (InterruptedException e) {
            log.error("occur exception when start server:", e);
        } finally {
            log.error("shutdown bossGroup and workerGroup");
            bossGroup.shutdownGracefully();
            workerGroup.shutdownGracefully();
            serviceHandlerGroup.shutdownGracefully();
        }
    }
}