#

public class C {
    public static void main(String[] args) {
        // 资源类
        Data3 data = new Data3();
        /**
         * 实现效果：A ==> B ==> C ==> A
         */
        new Thread(()->{
            for (int i = 0; i < 10; i++) {
                data.printA();
            }
        },"A").start();
        new Thread(()->{
            for (int i = 0; i < 10; i++) {
                data.printB();
            }
        },"B").start();
        new Thread(()->{
            for (int i = 0; i < 10; i++) {
                data.printC();
            }
        },"C").start();
    }
}

/**
 * 资源类
 */
class Data3{
    private Lock lock = new ReentrantLock();
    private Condition condition1 = lock.newCondition();
    private Condition condition2 = lock.newCondition();
    private Condition condition3 = lock.newCondition();
    /** 1A 2B 3C **/
    private int num = 1;

    public void printA(){
        // 加锁
        lock.lock();
        try {
            // 业务代码：判断 ==> 执行 ==> 通知
            while (num != 1){
                // 等待
                condition1.await();
            }

            System.out.println(Thread.currentThread().getName() + "==>printA");

            // 唤醒指定的人：B
            num = 2;
            condition2.signal();
        } catch (Exception e){
          e.printStackTrace();
        } finally {
            // 解锁
            lock.unlock();
        }
    }

    public void printB(){
        // 加锁
        lock.lock();
        try {
            // 业务代码：判断 ==> 执行 ==> 通知
            while (num != 2){
                condition2.await();
            }

            System.out.println(Thread.currentThread().getName() + "==>printB");

            // 唤醒指定的人：C
            num = 3;
            condition3.signal();
        } catch (Exception e){
            e.printStackTrace();
        } finally {
            // 解锁
            lock.unlock();
        }
    }

    public void printC(){
        // 加锁
        lock.lock();
        try {
            // 业务代码：判断 ==> 执行 ==> 通知
            while (num != 3){
                condition3.await();
            }

            System.out.println(Thread.currentThread().getName() + "==>printC");

            // 唤醒指定的人：A
            num = 1;
            condition1.signal();
        } catch (Exception e){
            e.printStackTrace();
        } finally {
            // 解锁
            lock.unlock();
        }
    }
}

执行结果：

A==>printA
B==>printB
C==>printC
A==>printA
B==>printB
C==>printC
A==>printA
B==>printB
C==>printC
A==>printA
B==>printB
C==>printC
A==>printA
B==>printB
C==>printC
A==>printA
B==>printB
C==>printC
A==>printA
B==>printB
C==>printC
A==>printA
B==>printB
C==>printC
A==>printA
B==>printB
C==>printC
A==>printA
B==>printB
C==>printC

Process finished with exit code