1、问题描述

用程序实现两个线程交替打印0-100的奇偶数

2、解题思路

让线程1打印之后唤醒其他线程，然后让出锁，自己进入休眠状态，因为进入了休眠状态就不会与其他线程争抢锁，此时只有线程2能获取锁，线程2以同样的逻辑执行，唤醒线程1并让出持有的锁，自己进入休眠状态。

代码

	private int count = 0;
    private final Object lock = new Object();
    public void turning() throws InterruptedException {
        Thread even = new Thread(() -> {
            while (count <= 100) {
                synchronized (lock) {
                    System.out.println("偶数: " + count++);
                    lock.notifyAll();
                    try {
                        // 如果还没有结束，则让出当前的锁并休眠
                        if (count <= 100) {
                            lock.wait();
                        }
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
            }
        });
        Thread odd = new Thread(() -> {
            while (count <= 100) {
                synchronized (lock) {
                    System.out.println("奇数: " + count++);
                    lock.notifyAll();
                    try {
                        // 如果还没有结束，则让出当前的锁并休眠
                        if (count <= 100) {
                            lock.wait();
                        }
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
            }
        });
        even.start();
        // 确保偶数线程线先获取到锁
        Thread.sleep(1);
        odd.start();
    }

public class TurningRunner implements Runnable {
    private  int count=0;
    private final  Object lock = new Object();
    @Override
    public void run() {
        while (count <= 100) {
            // 获取锁
            synchronized (lock) {
                // 拿到锁就打印
                System.out.println(Thread.currentThread().getName() + ": " + count++);
                // 唤醒其他线程
                lock.notifyAll();
                try {
                    if (count <= 100) {
                        // 如果任务还没有结束，则让出当前的锁并休眠
                        lock.wait();
                    }
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }
    }
}