多线程交替打印

打印0～100

public class multiThreadedPrinting {

    private static volatile int count = 0;
    private static final int MAX = 100;
    private static final Object LOCK = new Object();

    public static void main(String[] args) {
        Thread thread1 = new Thread(new Seq(0));
        Thread thread2 = new Thread(new Seq(1));
        thread1.start();
        thread2.start();
        thread1.join();
        thread2.join();
    }

    static class Seq implements Runnable {
        private final int index;

        public Seq(int index) {
            this.index = index;
        }

        @Override
        public void run() {
            while(count < MAX) {
                synchronized (LOCK) {
                    // 判断当前线程能不能打印？
                    while (count % 2 != index) {
                        try {
                            LOCK.wait();
                        } catch (Exception e) {
                            e.printStackTrace();
                        }
                    }

                    if(count > MAX) {
                        LOCK.notify();
                        return;
                    }
                    System.out.println("Thread " + index + ": " + count);
                    count++;
                    LOCK.notify();
                }
            }
        }
    }
}

打印 ABC

public class multiThreadedPrinting3 {
    private static final int count = 3;
    private static final Semaphore semA = new Semaphore(1);
    private static final Semaphore semB = new Semaphore(0);
    private static final Semaphore semC = new Semaphore(0);

    public static void main(String[] args) {
        new Thread(new Task("A", semA, semB)).start();
        new Thread(new Task("B", semB, semC)).start();
        new Thread(new Task("C", semC, semA)).start();
    }

    private static class Task implements Runnable {
        private final String value;
        private final Semaphore current;
        private final Semaphore next;

        public Task(String value, Semaphore current, Semaphore next) {
            this.value = value;
            this.current = current;
            this.next = next;
        }

        @Override
        public void run() {
            for(int i = 0; i < count; i ++) {
                try {
                    current.acquire();
                    System.out.println(value);
                    next.release();
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        }
    }
}