public class NamesrvStartup {
    ...
    public static void main(String[] args) {
        main0(args);
    }
    public static NamesrvController main0(String[] args) {
        try {
            // 創(chuàng)建 controller
            NamesrvController controller = createNamesrvController(args);
            // 啟動(dòng)
            start(controller);
            String tip = "The Name Server boot success. serializeType=" 
                    + RemotingCommand.getSerializeTypeConfigInThisServer();
            log.info(tip);
            System.out.printf("%s%n", tip);
            return controller;
        } catch (Throwable e) {
            e.printStackTrace();
            System.exit(-1);
        }
        return null;
    }
    ...
}

public static NamesrvController createNamesrvController(String[] args) 
        throws IOException, JoranException {
    // 省略解析命令行代碼
    ...
    // nameServer的相關(guān)配置
    final NamesrvConfig namesrvConfig = new NamesrvConfig();
    //  nettyServer的相關(guān)配置
    final NettyServerConfig nettyServerConfig = new NettyServerConfig();
    // 端口寫死了。。。
    nettyServerConfig.setListenPort(9876);
    if (commandLine.hasOption('c')) {
        // 處理配置文件
        String file = commandLine.getOptionValue('c');
        if (file != null) {
            // 讀取配置文件，并將其加載到 properties 中
            InputStream in = new BufferedInputStream(new FileInputStream(file));
            properties = new Properties();
            properties.load(in);
            // 將 properties 里的屬性賦值到 namesrvConfig 與 nettyServerConfig
            MixAll.properties2Object(properties, namesrvConfig);
            MixAll.properties2Object(properties, nettyServerConfig);
            namesrvConfig.setConfigStorePath(file);
            System.out.printf("load config properties file OK, %s%n", file);
            in.close();
        }
    }
    // 處理 -p 參數(shù)，該參數(shù)用于打印nameServer、nettyServer配置，省略
    ...
    // 將 commandLine 的所有配置設(shè)置到 namesrvConfig 中
    MixAll.properties2Object(ServerUtil.commandLine2Properties(commandLine), namesrvConfig);
    // 檢查環(huán)境變量：ROCKETMQ_HOME
    if (null == namesrvConfig.getRocketmqHome()) {
        // 如果不設(shè)置 ROCKETMQ_HOME，就會(huì)在這里報(bào)錯(cuò)
        System.out.printf("Please set the %s variable in your environment to match 
                the location of the RocketMQ installation%n", MixAll.ROCKETMQ_HOME_ENV);
        System.exit(-2);
    }
    // 省略日志配置
    ...
    // 創(chuàng)建一個(gè)controller
    final NamesrvController controller = 
            new NamesrvController(namesrvConfig, nettyServerConfig);
    // 將當(dāng)前 properties 合并到項(xiàng)目的配置中，并且當(dāng)前 properties 會(huì)覆蓋項(xiàng)目中的配置
    controller.getConfiguration().registerConfig(properties);
    return controller;
}

InputStream in = new BufferedInputStream(new FileInputStream(file));
properties = new Properties();
properties.load(in);

public static void properties2Object(final Properties p, final Object object) {
    Method[] methods = object.getClass().getMethods();
    for (Method method : methods) {
        String mn = method.getName();
        if (mn.startsWith("set")) {
            try {
                String tmp = mn.substring(4);
                String first = mn.substring(3, 4);
                // 首字母小寫
                String key = first.toLowerCase() + tmp;
                // 從Properties中獲取對應(yīng)的值
                String property = p.getProperty(key);
                if (property != null) {
                    // 獲取值，并進(jìn)行相應(yīng)的類型轉(zhuǎn)換
                    Class<?>[] pt = method.getParameterTypes();
                    if (pt != null && pt.length > 0) {
                        String cn = pt[0].getSimpleName();
                        Object arg = null;
                        // 轉(zhuǎn)換成int
                        if (cn.equals("int") || cn.equals("Integer")) {
                            arg = Integer.parseInt(property);
                        // 其他類型如long,double,float,boolean都是這樣轉(zhuǎn)換的，這里就省略了    
                        } else if (...) {
                            ...
                        } else {
                            continue;
                        }
                        // 反射調(diào)用
                        method.invoke(object, arg);
                    }
                }
            } catch (Throwable ignored) {
            }
        }
    }
}

final NamesrvController controller = new NamesrvController(namesrvConfig, nettyServerConfig);

/**
 * 構(gòu)造方法，一系列的賦值操作
 */
public NamesrvController(NamesrvConfig namesrvConfig, NettyServerConfig nettyServerConfig) {
    this.namesrvConfig = namesrvConfig;
    this.nettyServerConfig = nettyServerConfig;
    this.kvConfigManager = new KVConfigManager(this);
    this.routeInfoManager = new RouteInfoManager();
    this.brokerHousekeepingService = new BrokerHousekeepingService(this);
    this.configuration = new Configuration(log, this.namesrvConfig, this.nettyServerConfig);
    this.configuration.setStorePathFromConfig(this.namesrvConfig, "configStorePath");
}

public static NamesrvController main0(String[] args) {
    try {
        NamesrvController controller = createNamesrvController(args);
        start(controller);
        ...
    } catch (Throwable e) {
        e.printStackTrace();
        System.exit(-1);
    }
    return null;
}

public static NamesrvController start(final NamesrvController controller) throws Exception {
    if (null == controller) {
        throw new IllegalArgumentException("NamesrvController is null");
    }
    // 初始化
    boolean initResult = controller.initialize();
    if (!initResult) {
        controller.shutdown();
        System.exit(-3);
    }
    // 關(guān)閉鉤子，可以在關(guān)閉前進(jìn)行一些操作
    Runtime.getRuntime().addShutdownHook(new ShutdownHookThread(log, new Callable<Void>() {
        @Override
        public Void call() throws Exception {
            controller.shutdown();
            return null;
        }
    }));
    // 啟動(dòng)
    controller.start();
    return controller;
}

public boolean initialize() {
    // 加載 kv 配置
    this.kvConfigManager.load();
    // 創(chuàng)建 netty 遠(yuǎn)程服務(wù)
    this.remotingServer = new NettyRemotingServer(this.nettyServerConfig, 
            this.brokerHousekeepingService);
    // netty 遠(yuǎn)程服務(wù)線程
    this.remotingExecutor = Executors.newFixedThreadPool(
            nettyServerConfig.getServerWorkerThreads(), 
            new ThreadFactoryImpl("RemotingExecutorThread_"));
    // 注冊，就是把 remotingExecutor 注冊到 remotingServer
    this.registerProcessor();
    // 開啟定時(shí)任務(wù)，每隔10s掃描一次broker，移除不活躍的broker
    this.scheduledExecutorService.scheduleAtFixedRate(new Runnable() {
        @Override
        public void run() {
            NamesrvController.this.routeInfoManager.scanNotActiveBroker();
        }
    }, 5, 10, TimeUnit.SECONDS);
    // 省略打印kv配置的定時(shí)任務(wù)
    ...
    // Tls安全傳輸，我們不關(guān)注
    if (TlsSystemConfig.tlsMode != TlsMode.DISABLED) {
        ...
    }
    return true;
}

public NettyRemotingServer(final NettyServerConfig nettyServerConfig,
        final ChannelEventListener channelEventListener) {
    super(nettyServerConfig.getServerOnewaySemaphoreValue(), 
            nettyServerConfig.getServerAsyncSemaphoreValue());
    this.serverBootstrap = new ServerBootstrap();
    this.nettyServerConfig = nettyServerConfig;
    this.channelEventListener = channelEventListener;
    int publicThreadNums = nettyServerConfig.getServerCallbackExecutorThreads();
    if (publicThreadNums <= 0) {
        publicThreadNums = 4;
    }
    // 創(chuàng)建 publicExecutor
    this.publicExecutor = Executors.newFixedThreadPool(publicThreadNums, new ThreadFactory() {
        private AtomicInteger threadIndex = new AtomicInteger(0);
        @Override
        public Thread newThread(Runnable r) {
            return new Thread(r, "NettyServerPublicExecutor_" 
                    + this.threadIndex.incrementAndGet());
        }
    });
    // 判斷是否使用 epoll
    if (useEpoll()) {
        // boss
        this.eventLoopGroupBoss = new EpollEventLoopGroup(1, new ThreadFactory() {
            private AtomicInteger threadIndex = new AtomicInteger(0);
            @Override
            public Thread newThread(Runnable r) {
                return new Thread(r, String.format("NettyEPOLLBoss_%d", 
                    this.threadIndex.incrementAndGet()));
            }
        });
        // worker
        this.eventLoopGroupSelector = new EpollEventLoopGroup(
                nettyServerConfig.getServerSelectorThreads(), new ThreadFactory() {
            private AtomicInteger threadIndex = new AtomicInteger(0);
            private int threadTotal = nettyServerConfig.getServerSelectorThreads();
            @Override
            public Thread newThread(Runnable r) {
                return new Thread(r, String.format("NettyServerEPOLLSelector_%d_%d", 
                    threadTotal, this.threadIndex.incrementAndGet()));
            }
        });
    } else {
        // 這里也是創(chuàng)建了兩個(gè)線程
        ...
    }
    // 加載ssl上下文
    loadSslContext();
}

this.remotingExecutor = Executors.newFixedThreadPool(
    nettyServerConfig.getServerWorkerThreads(), 
    new ThreadFactoryImpl("RemotingExecutorThread_"));

this.registerProcessor();

private void registerProcessor() {
    if (namesrvConfig.isClusterTest()) {
        this.remotingServer.registerDefaultProcessor(
            new ClusterTestRequestProcessor(this, namesrvConfig.getProductEnvName()),
            this.remotingExecutor);
    } else {
        // 注冊操作
        this.remotingServer.registerDefaultProcessor(
            new DefaultRequestProcessor(this), this.remotingExecutor);
    }
}

@Override
public void registerDefaultProcessor(NettyRequestProcessor processor, ExecutorService executor) {
    this.defaultRequestProcessor 
            = new Pair<NettyRequestProcessor, ExecutorService>(processor, executor);
}

this.scheduledExecutorService.scheduleAtFixedRate(new Runnable() {
    @Override
    public void run() {
        NamesrvController.this.routeInfoManager.scanNotActiveBroker();
    }
}, 5, 10, TimeUnit.SECONDS);

public static NamesrvController start(final NamesrvController controller) throws Exception {
    ...
    // 啟動(dòng)
    controller.start();
    return controller;
}

public void start() throws Exception {
    // 啟動(dòng)nettyServer
    this.remotingServer.start();
    // 監(jiān)聽tls配置文件的變化，不關(guān)注
    if (this.fileWatchService != null) {
        this.fileWatchService.start();
    }
}

public void start() {
    ...
    ServerBootstrap childHandler =
        // 在 NettyRemotingServer#init 中準(zhǔn)備的兩個(gè)線程組
        this.serverBootstrap.group(this.eventLoopGroupBoss, this.eventLoopGroupSelector)
            .channel(useEpoll() ? EpollServerSocketChannel.class : NioServerSocketChannel.class)
            // 省略 option(...)與childOption(...)方法的配置
            ...
            // 綁定ip與端口
            .localAddress(new InetSocketAddress(this.nettyServerConfig.getListenPort()))
            .childHandler(new ChannelInitializer<SocketChannel>() {
                @Override
                public void initChannel(SocketChannel ch) throws Exception {
                    ch.pipeline()
                        .addLast(defaultEventExecutorGroup, 
                            HANDSHAKE_HANDLER_NAME, handshakeHandler)
                        .addLast(defaultEventExecutorGroup,
                            encoder,
                            new NettyDecoder(),
                            new IdleStateHandler(0, 0, 
                                nettyServerConfig.getServerChannelMaxIdleTimeSeconds()),
                            connectionManageHandler,
                            serverHandler
                        );
                }
            });
    if (nettyServerConfig.isServerPooledByteBufAllocatorEnable()) {
        childHandler.childOption(ChannelOption.ALLOCATOR, PooledByteBufAllocator.DEFAULT);
    }
    try {
        ChannelFuture sync = this.serverBootstrap.bind().sync();
        InetSocketAddress addr = (InetSocketAddress) sync.channel().localAddress();
        this.port = addr.getPort();
    } catch (InterruptedException e1) {
        throw new RuntimeException("this.serverBootstrap.bind().sync() InterruptedException", e1);
    }
    ...
}

ch.pipeline()
    .addLast(defaultEventExecutorGroup, 
        HANDSHAKE_HANDLER_NAME, handshakeHandler)
    .addLast(defaultEventExecutorGroup,
        encoder,
        new NettyDecoder(),
        new IdleStateHandler(0, 0, 
            nettyServerConfig.getServerChannelMaxIdleTimeSeconds()),
        connectionManageHandler,
        serverHandler
    );