今天想起前段時(shí)間的一道面試編程題，要求兩個線程實(shí)現(xiàn)打印奇偶數(shù)，當(dāng)時(shí)因?yàn)闆]能很好的理解wait和notify。所以代碼有問題。今天又查了下，重新試了下，先上正確結(jié)果：

偶數(shù)線程

public static class Thread1 extends Thread {

        Object lock;
        public Thread1(Object lock) {
            this.lock = lock;
        }

        @Override
        public void run() {
            super.run();
            synchronized (lock) {

                while (true && i < 100) {
                    if (i % 2 == 0) {
                        System.out.println("--Thread1-->" + i);
                        i++;
                        lock.notify();
                        try {
                            lock.wait();
                        } catch (InterruptedException e) {
                            e.printStackTrace();
                        }

                    }
                }
            }
        }
    }

奇數(shù)線程

public static class Thread2 extends Thread {

        Object lock;

        public Thread2(Object lock) {
            this.lock = lock;
        }

        @Override
        public void run() {
            super.run();
            synchronized (lock) {
                while (true && i < 100) {
                    if (i % 2 == 1) {
                        System.out.println("--Thread2-->" + i);
                        i++;
                        lock.notify();
                        try {
                            lock.wait();
                        } catch (InterruptedException e) {
                            e.printStackTrace();
                        }

                    }

                }
            }
        }
    }

主函數(shù)

public static void main(String[] args) {
        Object lock = new Object();
        Thread t1 = new Thread1(lock);
        Thread t2 = new Thread2(lock);
        t1.start();
        t2.start();
    }

可以簡單理解成lock.notify()是喚醒別人，lock.wait()是休眠自己。

而且要注意放在synchronized代碼塊中，否則會報(bào)IllegalMonitorStateException異常。