每日一问 - 两个线程交替打印 ABABAB

每日一问 - 两个线程交替打印 ABABAB…

问题

两个线程交替打印 ABABAB... ?
两个线程交替打印 ABABAB 打印 10 次？

解决方案

考的就是线程之间通信问题， 使用　wait, notify

交替打印AB

public class ABCoreHolder {

    private boolean flag = true;

    public void printA() throws Exception {
        synchronized (this) {
            while (!flag) {
                wait();

            }
            System.out.print("A");
            flag = false;
            TimeUnit.SECONDS.sleep(1);
            notify();
        }
    }

    public void printB() throws Exception {
        synchronized (this) {
            while (flag) {
                wait();
            }

            System.out.print("B");
            flag = true;
            TimeUnit.SECONDS.sleep(1);
            notify();
        }
    }

}

两个线程可以用 notify , 如果多的话，需要用 notifyAll !!

测试用例

    /**
     * A,B 交替打印
     * @throws InterruptedException
     */
    public static void abLoop() throws InterruptedException {
        final ABCoreHolder holder = new ABCoreHolder();
        Thread t1 = new Thread(new Runnable() {
            @Override
            public void run() {
                while (true) {
                    try {
                        holder.printA();
                    } catch (Exception e) {
                        e.printStackTrace();
                    }
                }
            }
        });

        Thread t2 = new Thread(new Runnable() {
            @Override
            public void run() {
                while (true) {
                    try {
                        holder.printB();
                    } catch (Exception e) {
                        e.printStackTrace();
                    }
                }
            }
        });

        t1.start();
        t2.start();
    }

结果 :

ABABABABABABABABABABABABABA...

交替打印 10 次 ABAB…

/**
     * A,B 交替打印共 10 次
     */
public static void ab10Loop() {
    final ABCoreHolder holder = new ABCoreHolder();
    Thread t1 = new Thread(new Runnable() {
        @Override
        public void run() {

            for (int i = 0; i < 10; i++) {
                try {
                    holder.printA();
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        }
    });

    Thread t2 = new Thread(new Runnable() {
        @Override
        public void run() {
            for (int i = 0; i < 10; i++) {
                try {
                    holder.printB();
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        }
    });

    t1.start();
    t2.start();
}

结果:

ABABABABABABABABABAB
Process finished with exit code 0

标签：Exception,ABABAB,Thread,void,打印,一问,线程,new,public
来源： https://blog.csdn.net/u013887008/article/details/120447689