java严格按照顺序执行两个独立的线程

Question

我想以严格的顺序执行两个独立的线程，即“A->；B->；A->；B”，谁知道如何执行

我不希望序列之间有任何延迟（如睡眠、产量）

以下是一些我编写但无法运行的代码：

    public void onClick_start_thread_a(View v) {
    logger.d("onClick_start_thread_a");
    Runnable r = new Runnable() {

        @Override
        public void run() {
            // TODO Auto-generated method stub
            while (true) {
                synchronized (flag) {
                    try {
                        flag.wait();
                    } catch (InterruptedException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                    logger.d("Thread A!");
                }
            }
        }
    };
    Thread t = new Thread(r);
    t.start();
}

public void onClick_start_thread_b(View v) {
    logger.d("onClick_start_thread_b");
    Runnable r = new Runnable() {
        @Override
        public void run() {
            // TODO Auto-generated method stub
            while (true) {
                synchronized (flag) {
                flag.notify();
                logger.d("Thread B!");
                }
            }
        }
    };
    Thread t = new Thread(r);
    t.start();
}

onClick_start_thread_a和onClick_start_thread_b由两个不同的按钮触发，单击按钮后，输出为：

01-11 22:49:40.705: D/THING(25877): {Thread:Thread-619}[MainActivity:] Thread A!
01-11 22:49:40.705: D/THING(25877): {Thread:Thread-620}[MainActivity:] Thread B!
01-11 22:49:40.705: D/THING(25877): {Thread:Thread-619}[MainActivity:] Thread A!
01-11 22:49:40.705: D/THING(25877): {Thread:Thread-620}[MainActivity:] Thread B!
01-11 22:49:40.705: D/THING(25877): {Thread:Thread-619}[MainActivity:] Thread A!
01-11 22:49:40.705: D/THING(25877): {Thread:Thread-620}[MainActivity:] Thread B!
01-11 22:49:40.705: D/THING(25877): {Thread:Thread-619}[MainActivity:] Thread A!
01-11 22:49:40.705: D/THING(25877): {Thread:Thread-620}[MainActivity:] Thread B!
01-11 22:49:40.705: D/THING(25877): {Thread:Thread-620}[MainActivity:] Thread B!
01-11 22:49:40.705: D/THING(25877): {Thread:Thread-620}[MainActivity:] Thread B!
01-11 22:49:40.705: D/THING(25877): {Thread:Thread-620}[MainActivity:] Thread B!
01-11 22:49:40.705: D/THING(25877): {Thread:Thread-620}[MainActivity:] Thread B!
01-11 22:49:40.705: D/THING(25877): {Thread:Thread-620}[MainActivity:] Thread B!
01-11 22:49:40.705: D/THING(25877): {Thread:Thread-620}[MainActivity:] Thread B!
01-11 22:49:40.705: D/THING(25877): {Thread:Thread-620}[MainActivity:] Thread B!
01-11 22:49:40.705: D/THING(25877): {Thread:Thread-620}[MainActivity:] Thread B!
01-11 22:49:40.705: D/THING(25877): {Thread:Thread-620}[MainActivity:] Thread B!
01-11 22:49:40.705: D/THING(25877): {Thread:Thread-620}[MainActivity:] Thread B!
01-11 22:49:40.705: D/THING(25877): {Thread:Thread-620}[MainActivity:] Thread B!
01-11 22:49:40.705: D/THING(25877): {Thread:Thread-620}[MainActivity:] Thread B!
01-11 22:49:40.705: D/THING(25877): {Thread:Thread-620}[MainActivity:] Thread B!

Answer 1

你可能想要的是某种信号量和麦加主义的信号

Start Threads A and B
B - waits on semaphore
A - does stuff
A - when finished A signals B
A - waits on semaphore
B - does stuff
B - when finished B signals A
...... repeat until done

看一下文档here

Answer 2

如果是像您这样的简单案例（只有两个线程），那么我认为您可以使用简单的布尔值（Java中的原子布尔值）

1）将布尔值（我们称之为decider）设置为false

2）启动两个线程

3）螺纹1将具有：

while(true) {
  if(decider.get()) {
    // do stuff
    decider.set(false);
  }
}

另一个：

while(true) {
  if(!decider.get()) {
    // do stuff
    decider.set(true);
  }
}

while（true）（或其他条件）似乎有点开销，因此您可以在两个if语句中添加一个锁（lock#lock（）将等待锁释放）

如果你想把它推广到更多的线程，你只需要用一些可以接受更多状态的东西来代替布尔值。每个线程可能有一个ID（从0到N），并且仅当invocationNr modulo nrOfThreads==ID时才会输入if

Answer 3

    public void onClick_start_thread_a(View v) {
    logger.d("onClick_start_thread_a");
    Runnable r = new Runnable() {

        @Override
        public void run() {
            // TODO Auto-generated method stub
            while (true) {
                synchronized (flag) {
                    System.out.println("Thread A!");
                    flag.notifyAll();
                    try
                    {
                        flag.wait();
                    } catch (InterruptedException e)
                    {
                        e.printStackTrace();
                    }
                }
            }
        }
    };
    Thread t = new Thread(r);
    t.start();
}

public void onClick_start_thread_b(View v) {
    logger.d("onClick_start_thread_b");
    Runnable r = new Runnable() {
        @Override
        public void run() {
            // TODO Auto-generated method stub
            while (true) {
                synchronized (flag) {
                    System.out.println("Thread B!");
                    flag.notifyAll();
                    try
                    {
                        flag.wait();
                    } catch (InterruptedException e)
                    {
                        e.printStackTrace();
                    }
                }
            }
        }
    };
    Thread t = new Thread(r);
    t.start();
}