Netty啟動流程伺服器端channel初始化原始碼分析

final ChannelFuture initAndRegister() {
    Channel channel = null;
    try {
        //建立channel
        channel = channelFactory.newChannel();
        //初始化channel
        init(channel);
    } catch (Throwable t) {
        //忽略非關鍵程式碼
    }
    ChannelFuture regFuture = config().group().register(channel);
    //忽略非關鍵程式碼
    return regFuture;
}

void init(Channel channel) throws Exception {
    //獲取使用者定義的選項(1)
    final Map<ChannelOption<?>, Object> options = options0();
    synchronized (options) {
        channel.config().setOptions(options);
    }

    //獲取使用者定義的屬性(2)
    final Map<AttributeKey<?>, Object> attrs = attrs0();
    synchronized (attrs) {
        for (Entry<AttributeKey<?>, Object> e: attrs.entrySet()) {
            @SuppressWarnings("unchecked")
            AttributeKey<Object> key = (AttributeKey<Object>) e.getKey();
            channel.attr(key).set(e.getValue());
        }
    }
    //獲取channel的pipline(3)
    ChannelPipeline p = channel.pipeline();
    //work執行緒組(4)
    final EventLoopGroup currentChildGroup = childGroup;
    //使用者設定的Handler(5)
    final ChannelHandler currentChildHandler = childHandler;
    final Entry<ChannelOption<?>, Object>[] currentChildOptions;
    final Entry<AttributeKey<?>, Object>[] currentChildAttrs;
    //選項轉化為Entry物件(6)
    synchronized (childOptions) { 
        currentChildOptions = childOptions.entrySet().toArray(newOptionArray(childOptions.size()));
    }
    //屬性轉化為Entry物件(7)
    synchronized (childAttrs) { 
        currentChildAttrs = childAttrs.entrySet().toArray(newAttrArray(childAttrs.size()));
    }
    //新增伺服器端handler(8)
    p.addLast(new ChannelInitializer<Channel>() {
        //初始化channel
        @Override
        public void initChannel(Channel ch) throws Exception {
            final ChannelPipeline pipeline = ch.pipeline();
            ChannelHandler handler = config.handler();
            if (handler != null) { 
                pipeline.addLast(handler);
            } 
            ch.eventLoop().execute(new Runnable() {
                @Override
                public void run() { 
                    pipeline.addLast(new ServerBootstrapAcceptor(
                            currentChildGroup, currentChildHandler, currentChildOptions, currentChildAttrs));
                }
            });
        }
    });
}