public class Reactor implements Runnable {

    ServerSocketChannel serverSocketChannel;
    Selector selector;

    public Reactor(int port) {
        try {
            serverSocketChannel = ServerSocketChannel.open();
            selector = Selector.open();
            serverSocketChannel.socket().bind(new InetSocketAddress(port));
            serverSocketChannel.configureBlocking(false);
            SelectionKey selectionKey = serverSocketChannel.register(selector, SelectionKey.OP_ACCEPT);
            selectionKey.attach(new Acceptor(serverSocketChannel));

        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    @Override
    public void run() {
        while (true) {
            try {
                selector.select();
                Set<SelectionKey> selectionKeys = selector.selectedKeys();
                Iterator<SelectionKey> iterator = selectionKeys.iterator();
                while (iterator.hasNext()) {
                    SelectionKey selectionKey = iterator.next();
                    dispatcher(selectionKey);
                    iterator.remove();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    private void dispatcher(SelectionKey selectionKey) {
        Runnable runnable = (Runnable) selectionKey.attachment();
        runnable.run();
    }
}

public class Acceptor implements Runnable {
    private ServerSocketChannel serverSocketChannel;
    private final int core = 8;
    private int index;
    private SubReactor[] subReactors = new SubReactor[core];
    private Thread[] threads = new Thread[core];
    private final Selector[] selectors = new Selector[core];

    public Acceptor(ServerSocketChannel serverSocketChannel) {
        this.serverSocketChannel = serverSocketChannel;
        for (int i = 0; i < core; i++) {
            try {
                selectors[i] = Selector.open();
            } catch (IOException e) {
                e.printStackTrace();
            }
            subReactors[i] = new SubReactor(selectors[i]);
            threads[i] = new Thread(subReactors[i]);
            threads[i].start();
        }
    }

    @Override
    public void run() {
        try {
            System.out.println("acceptor thread:" + Thread.currentThread().getName());

            SocketChannel socketChannel = serverSocketChannel.accept();
            System.out.println("有客户端连接上来了," + socketChannel.getRemoteAddress());
            socketChannel.configureBlocking(false);
            selectors[index].wakeup();
            SelectionKey selectionKey = socketChannel.register(selectors[index], SelectionKey.OP_READ);
            selectionKey.attach(new WorkerHandler(socketChannel));
            if (++index == threads.length) {
                index = 0;
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

public class SubReactor implements Runnable {

    private Selector selector;

    public SubReactor(Selector selector) {
        this.selector = selector;
    }

    @Override
    public void run() {
        while (true) {
            try {
                selector.select();
                System.out.println("selector:" + selector.toString() + "thread:" + Thread.currentThread().getName());
                Set<SelectionKey> selectionKeys = selector.selectedKeys();
                Iterator<SelectionKey> iterator = selectionKeys.iterator();
                while (iterator.hasNext()) {
                    SelectionKey selectionKey = iterator.next();
                    dispacher(selectionKey);
                    iterator.remove();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    private void dispacher(SelectionKey selectionKey) {
        Runnable runnable = (Runnable) selectionKey.attachment();
        runnable.run();
    }
}

public class WorkerHandler implements Runnable {
    private SocketChannel socketChannel;

    public WorkerHandler(SocketChannel socketChannel) {
        this.socketChannel = socketChannel;
    }

    @Override
    public void run() {
        try {
            System.out.println("workHandler thread:" + Thread.currentThread().getName());
            ByteBuffer buffer = ByteBuffer.allocate(1024);
            socketChannel.read(buffer);
            String message = new String(buffer.array(), StandardCharsets.UTF_8);
            System.out.println(socketChannel.getRemoteAddress() + "发来的消息：" + message);
            socketChannel.write(ByteBuffer.wrap("你的消息我收到了".getBytes(StandardCharsets.UTF_8)));

        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

/**
acceptor thread:main
有客户端连接上来了,/127.0.0.1:65194
selector:sun.nio.ch.KQueueSelectorImpl@5a506132thread:Thread-0
selector:sun.nio.ch.KQueueSelectorImpl@5a506132thread:Thread-0
workHandler thread:Thread-0
/127.0.0.1:65194发来的消息：123

acceptor thread:main
有客户端连接上来了,/127.0.0.1:65202
selector:sun.nio.ch.KQueueSelectorImpl@59887d72thread:Thread-1
selector:sun.nio.ch.KQueueSelectorImpl@59887d72thread:Thread-1
workHandler thread:Thread-1
/127.0.0.1:65202发来的消息：444
**/