JUC学习之线程通信小Demo

柔情只为你懂 2022-05-19 08:40 223阅读 0赞

按照顺序打印线程A、B、C，共打印五轮：

public class Test { 
    
        public static void main(String[] args) {
            AlternatePrinting printing = new AlternatePrinting();
            new Thread(() -> {
                for (int i = 1; i <= 5; i++) {
                    try {
                        printing.method1(i);
                    } catch (Exception e) {
                        e.printStackTrace();
                    }
                }
            }, "A").start();
    
            new Thread(() -> {
                for (int i = 1; i <= 5; i++) {
                    try {
                        printing.method2(i);
                    } catch (Exception e) {
                        e.printStackTrace();
                    }
                }
            }, "B").start();
    
            new Thread(() -> {
                for (int i = 1; i <= 5; i++) {
                    try {
                        printing.method3(i);
                        System.out.println("<------------我是可爱的分割线------------->");
                    } catch (Exception e) {
                        e.printStackTrace();
                    }
                }
            }, "C").start();
        }
    }
    
    class AlternatePrinting {
    
        private int number = 1;
        private Lock lock = new ReentrantLock();
        private Condition condition1 = lock.newCondition();
        private Condition condition2 = lock.newCondition();
        private Condition condition3 = lock.newCondition();
    
        public void method1(int time) throws Exception {
            lock.lock();
            try {
                if (number != 1) {
                        condition1.await();
                }
                System.out.println(Thread.currentThread().getName() + "\t" + time);
                number = 2;
                // 唤醒2
                condition2.signal();
            } finally {
                lock.unlock();
            }
        }
    
        public void method2(int time) throws Exception {
            lock.lock();
            try {
                if (number != 2) {
                    condition2.await();
                }
                System.out.println(Thread.currentThread().getName() + "\t" + time);
                number = 3;
                // 唤醒3
                condition3.signal();
            } finally {
                lock.unlock();
            }
        }
    
        public void method3(int time) throws Exception {
            lock.lock();
            try {
                if (number != 3) {
                    condition3.await();
                }
                System.out.println(Thread.currentThread().getName() + "\t" + time);
                number = 1;
                // 唤醒1
                condition1.signal();
            } finally {
                lock.unlock();
            }
        }
    }