java">public class Test9 {
    static Object lock = new Object();

    static int num = 1;
    static int loopNum = 5;

    /**
     * 线程t1, t2, t3分别交替输出 a, b, c => 最终输出 abcabcabcabcabc
     *
     */
    public static void main(String[] args) throws InterruptedException {
        Thread t1 = new Thread(() -> {
            f(1, 2, "a");
        }, "t1");

        Thread t2 = new Thread(() -> {
            f(2, 3, "b");
        }, "t2");

        Thread t3 = new Thread(() -> {
            f(3, 1, "c");
        }, "t3");
        t1.start();
        t2.start();
        t3.start();
    }

    private static void f(int current, int next, String word) {
        for (int i = 0; i < loopNum; i ++) {
            synchronized (lock) {
                while (current != num) {
                    try {
                        lock.wait();
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }

                System.out.print(word);
                num = next;
                lock.notifyAll();
            }
        }

    }
}

java">public class Test10 {
    static ReentrantLock lock = new ReentrantLock();
    static Condition a = lock.newCondition();
    static Condition b = lock.newCondition();
    static Condition c = lock.newCondition();

    static int loopNum = 5;

    /**
     * 线程t1, t2, t3分别交替输出 a, b, c => 最终输出 abcabcabcabcabc
     */
    public static void main(String[] args) throws InterruptedException {


        Thread t1 = new Thread(() -> {
            f(a, b, "a");
        }, "t1");

        Thread t2 = new Thread(() -> {
            f(b, c, "b");
        }, "t2");

        Thread t3 = new Thread(() -> {
            f(c, a, "c");
        }, "t3");
        t1.start();
        t2.start();
        t3.start();

        Thread.sleep(1000);
        lock.lock();
        try {
            System.out.println("开始...");
            a.signal();
        } finally {
            lock.unlock();
        }
    }

    private static void f(Condition current, Condition next, String word) {
        for (int i = 0; i < loopNum; i++) {
            lock.lock();
            try {
                current.await();
                System.out.print(word);
                next.signal();
            } catch (InterruptedException e) {
                e.printStackTrace();
            } finally {
                lock.unlock();
            }
        }
    }
}

java">public class Test11 {
    static ReentrantLock lock = new ReentrantLock();
    static Thread t1;
    static Thread t2;
    static Thread t3;

    static int loopNum = 5;

    /**
     * 线程t1, t2, t3分别交替输出 a, b, c => 最终输出 abcabcabcabcabc
     */
    public static void main(String[] args) throws InterruptedException {

        t1 = new Thread(() -> {
            f(t2, "a");
        }, "t1");

        t2 = new Thread(() -> {
            f(t3, "b");
        }, "t2");

        t3 = new Thread(() -> {
            f(t1, "c");
        }, "t3");
        t1.start();
        t2.start();
        t3.start();

        Thread.sleep(1000);
        LockSupport.unpark(t1);

    }

    private static void f(Thread next, String word) {
        for (int i = 0; i < loopNum; i ++) {
            LockSupport.park();
            System.out.print(word);
            LockSupport.unpark(next);
        }
    }
}