Juc02_Synchronized、ReentrantLock实现生产者和消费者问题（三）

2021-07-18 16:55:43

③. 使用ReentrantLock实现 (显示锁)

①. ReentrantLock( ):创建一个ReentrantLock的实例

②. void lock( ):获得锁

③. void unlock( ):释放锁

/*
* 使用Lock代替Synchronized来实现新版的生产者和消费者模式 !
* */
@SuppressWarnings("all")
public class ThreadWaitNotifyDemo {
    public static void main(String[] args) {
        AirCondition airCondition=new AirCondition();

        new Thread(()->{ for (int i = 0; i <10 ; i++) airCondition.decrement();},"线程A").start();
        new Thread(()->{ for (int i = 0; i <10 ; i++) airCondition.increment();},"线程B").start();
        new Thread(()->{ for (int i = 0; i <10 ; i++) airCondition.decrement();},"线程C").start();
        new Thread(()->{ for (int i = 0; i <10 ; i++) airCondition.increment();},"线程D").start();
    }
}
class AirCondition{
    private int number=0;
    //定义Lock锁对象
    final Lock lock=new ReentrantLock();
    final Condition condition  = lock.newCondition();

    //生产者,如果number=0就 number++
    public  void increment(){
       lock.lock();
       try {
           //1.判断
           while(number!=0){
               try {
                   condition.await();//this.wait();
               } catch (InterruptedException e) {
                   e.printStackTrace();
               }
           }
           //2.干活
           number++;
           System.out.println(Thread.currentThread().getName()+":\t"+number);
           //3.唤醒
           condition.signalAll();//this.notifyAll();
       }catch (Exception e){
           e.printStackTrace();
       }finally {
           lock.unlock();
       }
    }
    //消费者,如果number=1,就 number--
    public   void decrement(){
        lock.lock();
        try {
            //1.判断
            while(number==0){
                try {
                    condition.await();//this.wait();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
            //2.干活
            number--;
            System.out.println(Thread.currentThread().getName()+":\t"+number);
            //3.唤醒
            condition.signalAll();//this.notifyAll();
        }catch (Exception e){
            e.printStackTrace();
        }finally {
            lock.unlock();
        }
    }
}

Juc02_Synchronized、ReentrantLock实现生产者和消费者问题（三）

④. 精确通知

/*
    多个线程之间按顺序调用,实现A->B->C
三个线程启动,要求如下:
    AA打印5次,BB打印10次,CC打印15次
    接着
    AA打印5次,BB打印10次,CC打印15次
    ....来10轮
* */
public class ThreadOrderAccess {
    public static void main(String[] args) {
        ShareResource shareResource=new ShareResource();

        new Thread(()->{ for (int i = 1; i <=10; i++)shareResource.print5(); },"线程A").start();
        new Thread(()->{ for (int i = 1; i <=10; i++)shareResource.print10(); },"线程B").start();
        new Thread(()->{ for (int i = 1; i <=10; i++)shareResource.print15(); },"线程C").start();
    }
}

class ShareResource{

    //设置一个标识,如果是number=1,线程A执行...
    private int number=1;

    Lock lock=new ReentrantLock();
    Condition condition1=lock.newCondition();
    Condition condition2=lock.newCondition();
    Condition condition3=lock.newCondition();


    public void print5(){
        lock.lock();
        try {
            //1.判断
            while(number!=1){
                condition1.await();
            }
            //2.干活
            for (int i = 1; i <=5; i++) {
                System.out.println(Thread.currentThread().getName()+":\t"+i);
            }
            //3.唤醒
            number=2;
            condition2.signal();
        }catch (Exception e){
            e.printStackTrace();
        }finally {
            lock.unlock();
        }
    }

    public void print10(){
        lock.lock();
        try {
            //1.判断
            while(number!=2){
                condition2.await();
            }
            //2.干活
            for (int i = 1; i <=10; i++) {
                System.out.println(Thread.currentThread().getName()+":\t"+i);
            }
            //3.唤醒
            number=3;
            condition3.signal();
        }catch (Exception e){
            e.printStackTrace();
        }finally {
            lock.unlock();
        }
    }

    public void print15(){
        lock.lock();
        try {
            //1.判断
            while(number!=3){
                condition3.await();
            }
            //2.干活
            for (int i = 1; i <=15; i++) {
                System.out.println(Thread.currentThread().getName()+":\t"+i);
            }
            //3.唤醒
            number=1;
            condition1.signal();
        }catch (Exception e){
            e.printStackTrace();
        }finally {
            lock.unlock();
        }
    }
}

码农公寓

③. 使用ReentrantLock实现 (显示锁)

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