public class TestSelector {private static Selector selector;public static void main(String[] args) throws IOException, InterruptedException {startSelectorThread();Thread.sleep(2000);selector.wakeup();}private static void startSelectorThread(){Runnable selectorTask = () -> {try{String host = "127.0.0.1";int port = 8888;ServerSocketChannel serverSocketChannel = ServerSocketChannel.open();serverSocketChannel.configureBlocking(false);SocketAddress socketAddress = new InetSocketAddress(host, port);serverSocketChannel.bind(socketAddress);selector = Selector.open();while(true){serverSocketChannel.register(selector, SelectionKey.OP_ACCEPT);System.out.println("selector start select .....");Set<SelectionKey> selectionKeySet =  selector.selectedKeys();for(Iterator<SelectionKey> iterator = selectionKeySet.iterator(); iterator.hasNext(); ){SelectionKey selectionKey = iterator.next();System.out.println(selectionKey.toString());selectionKeySet.remove(selectionKey);ServerSocketChannel serverSocketChannel1 = (ServerSocketChannel) selectionKey.channel();SocketChannel clientChannel = serverSocketChannel1.accept();clientChannel.configureBlocking(false);clientChannel.register(selector, SelectionKey.OP_READ | SelectionKey.OP_WRITE);iterator.remove();}System.out.println("selector end select ....");}}catch (Exception e){e.printStackTrace();}}; //taskThread thread = new Thread(selectorTask);thread.start();}
}

/*** Causes the first selection operation that has not yet returned to return* immediately.** <p> If another thread is currently blocked in an invocation of the* {@link #select()} or {@link #select(long)} methods then that invocation* will return immediately.  If no selection operation is currently in* progress then the next invocation of one of these methods will return* immediately unless the {@link #selectNow()} method is invoked in the* meantime.  In any case the value returned by that invocation may be* non-zero.  Subsequent invocations of the {@link #select()} or {@link* #select(long)} methods will block as usual unless this method is invoked* again in the meantime.** <p> Invoking this method more than once between two successive selection* operations has the same effect as invoking it just once.  </p>** @return  This selector*/public abstract Selector wakeup();

public Selector wakeup() {Object var1 = this.interruptLock;synchronized(this.interruptLock) {if (!this.interruptTriggered) {this.pollWrapper.interrupt();this.interruptTriggered = true;}return this;}}