java - 让线程只是等待

Question

请告诉我如何让线程等待。例如，如果 i == 0 则等待，当 i == 1

时再次进行

public class Main {

    public Main() { 
    }

    public void method() {

            Thread thread = new Thread(new Task());
            // I want to make wait it when I want
            // for example wait if i == 0 and go again when i = 1
    }

    public static void main(String[] args) {
            new Main();
    }
}

Answer 1

这适用于 CountDownLatch .

    public static void main( String[] args ) throws Exception {
    final CountDownLatch latch = new CountDownLatch( 1 );
    System.out.println( "Starting main thread" );
    new Thread( new Runnable() {
        public void run() {
            System.out.println( "Starting second thread" );
            System.out.println( "Waiting in second thread" );
            try {
                latch.await();
            } catch ( InterruptedException e ) {
                e.printStackTrace();
            }
            System.out.println( "Stopping second thread" );
        }
    } ).start();

    Thread.sleep( 5000 );
    System.out.println( "Countdown in main thread" );
    latch.countDown();

    Thread.sleep( 1000 );
    System.out.println( "Stopping main thread" );
}