两线程实现奇偶交替打印

一时失言乱红尘 2024-04-17 22:35 82阅读 0赞

两种方式实现：

1 通过wait（）/notifyall（）方法实现

/*
    两条线程实现交替打印奇偶数
     */
    public class ThreadExchange {
    
        private static Object lock = new Object();
    
        private static int i = 1;
    
        public static void main(String[] args) {
            Thread t1 = new Thread(new Thread1());
            Thread t2 = new Thread(new Thread2());
            t1.start();
            t2.start();
        }
    
        static class  Thread1 implements Runnable{
            @Override
            public void run() {
                while (i<=100){
                    synchronized (lock){
                        if (i%2==1){
                            System.out.println("Thread1  " + i++);
                        }else {
                            lock.notifyAll();
                            try {
                                lock.wait(1000);
                            } catch (InterruptedException e) {
                                e.printStackTrace();
                            }
                        }
                    }
                }
            }
        }
        static class  Thread2 implements Runnable{
            @Override
            public void run() {
                while (i<=100){
                    synchronized (lock){
                        if (i%2==0){
                            System.out.println("Thread2  " + i++);
                        }else {
                            lock.notifyAll();
                            try {
                                lock.wait(1000);
                            } catch (InterruptedException e) {
                                e.printStackTrace();
                            }
                        }
                    }
                }
            }
        }
    }

2 通过volatile+自旋锁实现

public class ThreadExchange1 {
        private static volatile int i = 1;
        public static void main(String[] args) {
            new Thread(new PrintRunner(1),"ji shu").start();
            new Thread(new PrintRunner(0),"ou shu").start();
    
        }
        static class PrintRunner implements Runnable{
            private int result;
            public PrintRunner(int i) {result = i;}
            @Override
            public void run() {
                while(i < 10){
                    // 据说用除余运算也一样，因为编译器优化过了
                    if((i & 1) == result){
                        System.out.println(Thread.currentThread().getName() + i);
                        // 这里必须要在打印完后进行加操作
                        i++;
                    }
                }
            }
        }
    }