服务端Channel初始化及注册

创建服务端Channel

bind()

private ChannelFuture doBind(final SocketAddress localAddress) {
        final ChannelFuture regFuture = this.initAndRegister();
        final Channel channel = regFuture.channel();
        if (regFuture.cause() != null) { // 异常直接返回
            return regFuture;
        } else if (regFuture.isDone()) { // initAndRegister执行完毕，执行doBind0进行Socket绑定
            ChannelPromise promise = channel.newPromise();
            doBind0(regFuture, channel, localAddress, promise);
            return promise;
        } else { // initAndRegister还没有执行结束，添加回调监听，同样进行doBind0
            final AbstractBootstrap.PendingRegistrationPromise promise = new AbstractBootstrap.PendingRegistrationPromise(channel);
            regFuture.addListener(new ChannelFutureListener() {
                public void operationComplete(ChannelFuture future) throws Exception {
                    Throwable cause = future.cause();
                    if (cause != null) {
                        promise.setFailure(cause);
                    } else {
                        promise.registered();
                        AbstractBootstrap.doBind0(regFuture, channel, localAddress, promise);
                    }

                }
            });
            return promise;
        }
    }

initAndRegister()

final ChannelFuture initAndRegister() {
        Channel channel = null;

        try {
            channel = this.channelFactory.newChannel(); // 1.创建Channel（工厂通过反射创建Channel）
            this.init(channel); // 2.初始化Channel
        } catch (Throwable var3) {
            if (channel != null) {
                channel.unsafe().closeForcibly();
                return (new DefaultChannelPromise(channel, GlobalEventExecutor.INSTANCE)).setFailure(var3);
            }

            return (new DefaultChannelPromise(new FailedChannel(), GlobalEventExecutor.INSTANCE)).setFailure(var3);
        }

        ChannelFuture regFuture = this.config().group().register(channel); // 3.注册Channel
        if (regFuture.cause() != null) {
            if (channel.isRegistered()) {
                channel.close();
            } else {
                channel.unsafe().closeForcibly();
            }
        }

        return regFuture;
    }

NioServerSocketChannel.java

通过反射创建NioServerSocketChannel

provider.openServerSocketChannel()

private static java.nio.channels.ServerSocketChannel newChannel(SelectorProvider provider, InternetProtocolFamily family) {
        try {
            java.nio.channels.ServerSocketChannel channel = (java.nio.channels.ServerSocketChannel)SelectorProviderUtil.newChannel(OPEN_SERVER_SOCKET_CHANNEL_WITH_FAMILY, provider, family);
            return channel == null ? provider.openServerSocketChannel() : channel;
        } catch (IOException var3) {
            throw new ChannelException("Failed to open a socket.", var3);
        }
    }

SelectorProvider 只是接口，具体实现根据操作系统不同返回不同的实现类

具体参考DefalutSelectorProvider的源码实现

Untitled

AbstractChannel

protected AbstractChannel(Channel parent) {
        this.parent = parent;
        this.id = this.newId();
        this.unsafe = this.newUnsafe();
        this.pipeline = this.newChannelPipeline();
    }

初始化服务端Channel

Channel Initializer