下面接著看下面這段程式碼

//Binder裡面的程式碼
  public void channelOpen(
                ChannelHandlerContext ctx,
                ChannelStateEvent evt) {

            try {
                evt.getChannel().getConfig().setPipelineFactory(getPipelineFactory());

                // Split options into two categories: parent and
 
 child.
                Map<String, Object> allOptions = getOptions();
                Map<String, Object> parentOptions = new HashMap<String, Object>();
                for (Entry<String, Object> e: allOptions.entrySet()) {
                    if (e.getKey().startsWith("child."
 
)) {
                        childOptions.put(
                                e.getKey().substring(6),
                                e.getValue());
                    } else if (!e.getKey().equals("pipelineFactory")) {
                        parentOptions.put(e.getKey(), e.getValue());
                    }
                }

                // Apply parent options.
                evt.getChannel
 
().getConfig().setOptions(parentOptions);
            } finally {
                ctx.sendUpstream(evt);
            }
//evt.getChannel().bind()這裡開始呼叫繫結本地介面, 進入裡面看下面的情況
            boolean finished = futureQueue.offer(evt.getChannel().bind(localAddress));
            assert finished;
        }

 public static ChannelFuture bind(Channel channel, SocketAddress localAddress) {
        if (localAddress == null) {
            throw new NullPointerException("localAddress");
        }
        ChannelFuture future = future(channel);
        //像pipeline傳送一個bound訊息, 裡面儲存本地地址, 接著看裡面的寫法。
        channel.getPipeline().sendDownstream(new DownstreamChannelStateEvent(
                channel, future, ChannelState.BOUND, localAddress));
        return future;
    }

//DefaultPipeLine.java
    public void sendDownstream(ChannelEvent e) {
        DefaultChannelHandlerContext tail = getActualDownstreamContext(this.tail);
        if (tail == null) {
            try {
                //getSink() 這個sink是在channel裡面放入的NioServerSocketPipelineSink， 裡面還放了NioWorker,嘿嘿
                getSink().eventSunk(this, e);
                return;
            } catch (Throwable t) {
                notifyHandlerException(e, t);
                return;
            }
        }

        sendDownstream(tail, e);
    }

 //NioServerSocketPipelineSink.java 進入這個裡面
 private void handleServerSocket(ChannelEvent e) {
        if (!(e instanceof ChannelStateEvent)) {
            return;
        }

        ChannelStateEvent event = (ChannelStateEvent) e;
        NioServerSocketChannel channel =
            (NioServerSocketChannel) event.getChannel();
        ChannelFuture future = event.getFuture();
        ChannelState state = event.getState();
        Object value = event.getValue();

        switch (state) {
        case OPEN:
            if (Boolean.FALSE.equals(value)) {
                close(channel, future);
            }
            break;
        case BOUND:
            if (value != null) {
                //進入這個方法裡面, 進行介面的繫結
                bind(channel, future, (SocketAddress) value);
            } else {
                close(channel, future);
            }
            break;
        }
    }

  private void bind(
            NioServerSocketChannel channel, ChannelFuture future,
            SocketAddress localAddress) {

        boolean bound = false;
        boolean bossStarted = false;
        try {
            //socket繫結bind
            channel.socket.socket().bind(localAddress, channel.getConfig().getBacklog());
            bound = true;

            future.setSuccess();
            //觸發bound事件
            fireChannelBound(channel, channel.getLocalAddress());

            Executor bossExecutor =
                ((NioServerSocketChannelFactory) channel.getFactory()).bossExecutor;
            //它的作用是將bossExecutor 和Boss繫結在一起。
            DeadLockProofWorker.start(
                    bossExecutor,
                    new ThreadRenamingRunnable(
                            //主要看new Boss()這個裡面的實現
                            new Boss(channel),
                            "New I/O server boss #" + id + " (" + channel + ')'));
            bossStarted = true;
        } catch (Throwable t) {
            future.setFailure(t);
            fireExceptionCaught(channel, t);
        } finally {
            if (!bossStarted && bound) {
                close(channel, future);
            }
        }
    }

//Boss.java 
Boss(NioServerSocketChannel channel) throws IOException {
            //channel是netty封裝的一成NioServerChannel
            this.channel = channel;
            //開啟一個選擇，nio裡面的東西。 選擇器
            selector = Selector.open();
            //標誌
            boolean registered = false;
            try {
                // channel.socket 是nio裡面的NioServerChannel裡面的東西， register註冊accept事件， 一有客戶連線上來進去在selector能找到。
                channel.socket.register(selector, SelectionKey.OP_ACCEPT);
                registered = true;
            } finally {
                if (!registered) {
                    closeSelector();
                }
            }
            //嘿嘿， 記住這裡把selector放進去了。
            channel.selector = selector;
        }
  //上面的DeadLockProofWorker.start（）有啟動這個執行緒
        public void run() {
            final Thread currentThread = Thread.currentThread();
            //這裡使用鎖， 來防止高併發
            channel.shutdownLock.lock();
            try {
                for (;;) {
                    try {

                        if (selector.select(1000) > 0) {
                            selector.selectedKeys().clear();
                        }
                        //接收客戶端socket, 當客戶端有連入時，這裡會記錄
                        SocketChannel acceptedSocket = channel.socket.accept();
                        if (acceptedSocket != null) {
//註冊接入進來的客戶端                            registerAcceptedChannel(acceptedSocket, currentThread);
                        }
                    } catch (SocketTimeoutException e) {
                        // Thrown every second to get ClosedChannelException
                        // raised.
                    } catch (CancelledKeyException e) {
                        // Raised by accept() when the server socket was closed.
                    } catch (ClosedSelectorException e) {
                        // Raised by accept() when the server socket was closed.
                    } catch (ClosedChannelException e) {
                        // Closed as requested.
                        break;
                    } catch (Throwable e) {
                        logger.warn(
                                "Failed to accept a connection.", e);
                        try {
                            Thread.sleep(1000);
                        } catch (InterruptedException e1) {
                            // Ignore
                        }
                    }
                }
            } finally {
                channel.shutdownLock.unlock();
                closeSelector();
            }
        }

                private void registerAcceptedChannel(SocketChannel acceptedSocket, Thread currentThread) {
            try {
                ChannelPipeline pipeline =
//channel.getConfig()放入的 是我們自己重新的方法.這一段,所以裡面的getPipeline()就把我們直接寫的handler嵌入進來了。
 /*        bootstrap.setPipelineFactory(new ChannelPipelineFactory() {  
            public ChannelPipeline getPipeline() throws Exception {  
                return Channels.pipeline(new StringDecoder(), new StringEncoder(), new ServerHandler());  
            }  
        });*/                     channel.getConfig().getPipelineFactory().getPipeline();
                NioWorker worker = nextWorker();
                //從這裡進入
                worker.register(new NioAcceptedSocketChannel(
                        channel.getFactory(), pipeline, channel,
                        NioServerSocketPipelineSink.this, acceptedSocket,
                        worker, currentThread), null);
            } catch (Exception e) {
                logger.warn(
                        "Failed to initialize an accepted socket.", e);
                try {
                    acceptedSocket.close();
                } catch (IOException e2) {
                    logger.warn(
                            "Failed to close a partially accepted socket.",
                            e2);
                }
            }
        }

    //NioWorker.java
    void register(NioSocketChannel channel, ChannelFuture future) {

        boolean server = !(channel instanceof NioClientSocketChannel);
        //channel是和registerTask關聯的， 沒一個客戶端連線都會繫結一個執行緒。
        Runnable registerTask = new RegisterTask(channel, future, server);
        //臨時選擇器
        Selector selector;

        synchronized (startStopLock) {
            //注意這裡， 這裡只會執行一次if裡面的程式碼
            if (!started) { 
                // Open a selector if this worker didn't start yet.
                try {
                    //選擇器
                    this.selector = selector = Selector.open();
                } catch (Throwable t) {
                    throw new ChannelException(
                            "Failed to create a selector.", t);
                }

                // Start the worker thread with the new Selector.
                String threadName =
                    (server ? "New I/O server worker #"
                            : "New I/O client worker #") + bossId + '-' + id;

                boolean success = false;
                try {
                    DeadLockProofWorker.start(
                            executor, new ThreadRenamingRunnable(this, threadName));
                    success = true;
                } finally {
                    if (!success) {
                        // Release the Selector if the execution fails.
                        try {
                            selector.close();
                        } catch (Throwable t) {
                            logger.warn("Failed to close a selector.", t);
                        }
                        this.selector = selector = null;
                        // The method will return to the caller at this point.
                    }
                }
            } else {
                // Use the existing selector if this worker has been started.
                selector = this.selector;
            }

            assert selector != null && selector.isOpen();

            started = true;
            //把註冊的任務放入到 registerTaskQueue裡面
            boolean offered = registerTaskQueue.offer(registerTask);
            assert offered;
        }

        if (wakenUp.compareAndSet(false, true)) {
            selector.wakeup();
        }
    }

今天就暫時說到這裡， 有什麼不明白的。可以問我。