Netty分析--Channel的创建

服务端的socket在哪里初始化的？

在哪里accpet连接的？

Netty服务端启动

创建服务端Channel

初始化服务端Channel

注册selector

端口绑定

1.创建服务端Channel

//创建服务端Channel的入口
ChannelFuture f = b.bind(8888).sync();

//进入bind
public ChannelFuture bind(int inetPort) {
        return this.bind(new InetSocketAddress(inetPort));
    }
//进入bind
 public ChannelFuture bind(SocketAddress localAddress) {
        this.validate();
        if (localAddress == null) {
            throw new NullPointerException("localAddress");
        } else {
            return this.doBind(localAddress);
        }
    }
//进入doBind()
 private ChannelFuture doBind(final SocketAddress localAddress) {
        final ChannelFuture regFuture = this.initAndRegister();
        final Channel channel = regFuture.channel();
        if (regFuture.cause() != null) {
            return regFuture;
        } else if (regFuture.isDone()) {
            ChannelPromise promise = channel.newPromise();
            doBind0(regFuture, channel, localAddress, promise);
            return promise;
        } else {
            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;
        }
    }
//在此initAndRegidter()种进行创建
final ChannelFuture initAndRegister() {
        Channel channel = null;

        try {
            channel = this.channelFactory.newChannel();
            this.init(channel);
        } catch (Throwable var3) {
            if (channel != null) {
                channel.unsafe().closeForcibly();
            }

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

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

        return regFuture;
    }

最后发现是在channelFactory通过反射创建的。
下面是对反射创建服务端Channel的解析

1.newSocket():通过jdk来创建底层jdk channel
2.NioServerSocketChannelConfig():tcp参数配置类
3.AbstractNioChannel()
   configureBlocking(false)：阻塞模式
   AbstractChannel():创建id,unsafe,pipeline

//1.newSocket()方法
public NioServerSocketChannel() {
        this(newSocket(DEFAULT_SELECTOR_PROVIDER));
    }

//这个openServerSocketChannel()是调用java底层包创建一个Socket
private static java.nio.channels.ServerSocketChannel newSocket(SelectorProvider provider) {
        try {
            return provider.openServerSocketChannel();
        } catch (IOException var2) {
            throw new ChannelException("Failed to open a server socket.", var2);
        }
    }
//2.NioServerSocketChannelConfig()
public NioServerSocketChannel(java.nio.channels.ServerSocketChannel channel) {
        super((Channel)null, channel, 16);
        this.config = new NioServerSocketChannel.NioServerSocketChannelConfig(this, this.javaChannel().socket());
    }
//3.AbstractNioChannel()设置阻塞模式
protected AbstractNioChannel(Channel parent, SelectableChannel ch, int readInterestOp) {
        super(parent);
        this.ch = ch;
        this.readInterestOp = readInterestOp;

        try {
            ch.configureBlocking(false);
        } catch (IOException var7) {
            try {
                ch.close();
            } catch (IOException var6) {
                if (logger.isWarnEnabled()) {
                    logger.warn("Failed to close a partially initialized socket.", var6);
                }
            }

            throw new ChannelException("Failed to enter non-blocking mode.", var7);
        }
    }
//  AbstractChannel():创建id,unsafe,pipeline
 protected AbstractChannel(Channel parent) {
        this.parent = parent;
        this.id = this.newId();
    //对于tcp底层的操作
        this.unsafe = this.newUnsafe();
        this.pipeline = this.newChannelPipeline();
    }

2.init():初始化服务端Channel

init():初始化入口
   1.set ChannelOptions,ChannelAttrs
   2.set ChildOptions,ChildAttrs
   3.config handler :配置服务端pipeline
   4.add ServerBootstrapAcceptor:添加连接器

//1.用户自定义的属性放在Channel中
void init(Channel channel) throws Exception {
        Map, Object> options = this.options0();
        synchronized(options) {
            channel.config().setOptions(options);
        }

        Map, Object> attrs = this.attrs0();
        synchronized(attrs) {
            Iterator i$ = attrs.entrySet().iterator();

            while(true) {
                if (!i$.hasNext()) {
                    break;
                }

                Entry, Object> e = (Entry)i$.next();
                AttributeKey