用三个线程控制循环输出10次ABC

最新推荐文章于 2023-07-08 10:13:40 发布

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最新推荐文章于 2023-07-08 10:13:40 发布

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分类专栏：多线程

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本文介绍了如何使用Java的synchronized、wait()、notify()和notifyAll()方法实现三个线程协同工作，按序输出'ABCABC…ABC'字符串序列，每个线程分别负责输出'A'、'B'、'C'，循环10次。

public class PrintABC_Condition {

    private Lock lock = new ReentrantLock();

    private Condition conditionA = lock.newCondition();
    private Condition conditionB = lock.newCondition();
    private Condition conditionC = lock.newCondition();

    private char currThreadName = 'A';

    public void printABC(){
        System.out.println();
        Thread threadA = new Thread(new ThreadA());
        Thread threadB = new Thread(new ThreadB());
        Thread threadC = new Thread(new ThreadC());
        threadA.start();
        threadB.start();
        threadC.start();
    }

    private class ThreadA implements Runnable {

        @Override
        public void run() {
            for (int i = 0; i < 10; ++i) {
                lock.lock();
                try {
                    while (currThreadName != 'A') {
                        try {
                            conditionA.await();
                        } catch (InterruptedException e) {
                            e.printStackTrace();
                        }
                    }
                    System.out.print("A");
                    currThreadName = 'B';
                    conditionB.signal();
                }finally {
                    lock.unlock();
                }
            }
        }
    }

    private class ThreadB implements Runnable {

        @Override
        public void run() {
            for (int i = 0; i < 10; ++i) {
                lock.lock();
                try {
                    while (currThreadName != 'B') {
                        try {
                            conditionB.await();
                        } catch (InterruptedException e) {
                            e.printStackTrace();
                        }
                    }
                    System.out.print("B");
                    currThreadName = 'C';
                    conditionC.signal();
                }finally {
                    lock.unlock();
                }
            }
        }
    }

    private class ThreadC implements Runnable {

        @Override
        public void run() {
            for (int i = 0; i < 10; ++i) {
                lock.lock();
                try {
                    while (currThreadName != 'C') {
                        try {
                            conditionC.await();
                        } catch (InterruptedException e) {
                            e.printStackTrace();
                        }
                    }
                    System.out.print("C");
                    currThreadName = 'A';
                    conditionA.signal();
                }finally {
                    lock.unlock();
                }
            }
        }
    }
}

public class PrintABC_Syn {

    private char currThreadName = 'A';

    public PrintABC_Syn() {
       
    }

    public void printABC() {
        Thread threadA = new Thread(new PrintATask());
        Thread threadB = new Thread(new PrintBTask());
        Thread threadC = new Thread(new PrintCTask());

        threadA.start();
        threadB.start();
        threadC.start();
    }

    private synchronized void printA() {
        try {
            while (currThreadName != 'A') {
                wait();
            }
            System.out.print("A");
            currThreadName = 'B';
            notifyAll();
        } catch (InterruptedException e) {
            e.printStackTrace();
            notifyAll();
        }
    }

    private synchronized void printB() {
        try {
            while (currThreadName != 'B') {
                wait();
            }
            System.out.print("B");
            currThreadName = 'C';
            notifyAll();
        } catch (InterruptedException e) {
            e.printStackTrace();
            notifyAll();
        }
    }

    private synchronized void printC() {
        try {
            while (currThreadName != 'C') {
                wait();
            }
            System.out.print("C");
            currThreadName = 'A';
            notifyAll();
        } catch (InterruptedException e) {
            e.printStackTrace();
            notifyAll();
        }
    }

    private class PrintATask implements Runnable {

        @Override
        public void run() {
            for (int i = 0; i < 10; ++i){
                 printA();
            }
        }
    }

    private class PrintBTask implements Runnable {

        @Override
        public void run() {
            for (int i = 0; i < 10; ++i){
                printB();
            }
        }
    }

    private class PrintCTask implements Runnable {

        @Override
        public void run() {
            for (int i = 0; i < 10; ++i){
                printC();
            }
        }
    }

}

public class PrintABC_Lock {

    private static final int MAXN = 30;

    private AtomicInteger sycValue = new AtomicInteger(0);

    public void printABC(){
        Thread threadA = new Thread(new ABCRunnable());
        Thread threadB = new Thread(new ABCRunnable());
        Thread threadC = new Thread(new ABCRunnable());
        threadA.start();
        threadB.start();
        threadC.start();
    }

    private class ABCRunnable implements Runnable{

        @Override
        public void run() {
            while (sycValue.get() < MAXN){
                if (sycValue.get() % 3 == 0){
                    System.out.print("A");
                    sycValue.getAndIncrement();
                }else if (sycValue.get() % 3 == 1){
                    System.out.print("B");
                    sycValue.getAndIncrement();
                }else if (sycValue.get() % 3 == 2) {
                    System.out.print("C");
                    sycValue.getAndIncrement();
                }
            }
        }
    }

}

1. 请使用Java提供的synchronized块、wait()、notify()和notifyAll()方法，实现三个并发执行的线程1、2和3协同输出ABCABC…ABC这样的字符串序列（序列中ABC重复出现10次），其中线程1负责打印输出字母A，线程2负责打印输出字母B，线程3负责打印输出字母C。