JUC并发编程-生产者消费者实例

Posted 2022-02-13 NeverOW

生产者消费者实例

1.ReentrantLock实现

public class Demo 
    public static void main(String[] args) 
        Data data=new Data();

        //两个生产者线程
        for (int i = 0; i < 2; i++) 
            new Thread(()->
                try 
                    data.increment();
                 catch (InterruptedException e) 
                    e.printStackTrace();
                
            ,"生产者"+String.valueOf(i)).start();
        

        //两个消费者线程
        for (int i = 2; i < 4; i++) 
            new Thread(()->
                try 
                    data.decrement();
                 catch (InterruptedException e) 
                    e.printStackTrace();
                
            ,"消费者"+String.valueOf(i)).start();
        
    


class Data
    //共享资源
    private int number=0;


    Lock lock=new ReentrantLock();

    Condition condition= lock.newCondition();

    public void increment() throws InterruptedException 
        //上锁
        lock.lock();

        try 
            //循环判断条件，不用if避免虚假唤醒
            while (number!=0)
                //不满足条件就等待
                condition.await();
            
            //操作 生产
            number++;
            System.out.println(Thread.currentThread().getName()+"线程\\t"+number);
            //通知唤醒等待的消费者线程
            condition.signalAll();

         catch (InterruptedException e) 
            e.printStackTrace();
        
        //解锁
        lock.unlock();
    


    public void decrement() throws InterruptedException 
        //上锁
        lock.lock();

        try 
            while (number==0)
                condition.await();
            

            number--;
            System.out.println(Thread.currentThread().getName()+"线程\\t"+number);
            condition.signalAll();

         catch (InterruptedException e) 
            e.printStackTrace();
        


        lock.unlock();
    

2.阻塞队列实现

public class 阻塞队列版 
    public static void main(String[] args) 
            MyResource myResource=new MyResource(new ArrayBlockingQueue(10));

            new Thread(()->
                System.out.println("生产线程启动");
                try 
                    myResource.myProd();
                 catch (InterruptedException e) 
                    e.printStackTrace();
                
            ,"Prod").start();

            new Thread(()->
                System.out.println("消费线程启动");
                try 
                    myResource.myConsumer();
                 catch (InterruptedException e) 
                    e.printStackTrace();
                
            ,"Consumer").start();

        try 
            Thread.sleep(5000);
            System.out.println();
            System.out.println();
            System.out.println();
            System.out.println();

            myResource.stop();
            System.out.println("5秒时间到，老板main线程叫停");
         catch (InterruptedException e) 
        
    


class MyResource

    //默认开启，开始生产消费
    private volatile boolean FLAG=true;

    private AtomicInteger atomicInteger=new AtomicInteger();

    BlockingQueue<String> blockingQueue=null;

    public MyResource(BlockingQueue blockingQueue1)
        blockingQueue=blockingQueue1;
        System.out.println(blockingQueue1.getClass().getName());
    

    //生产方法
    public void myProd() throws InterruptedException 
        String data=null;
        boolean result;

        while (FLAG)

           data=atomicInteger.incrementAndGet()+"";
           result=blockingQueue.offer(data,2L, TimeUnit.SECONDS);
           if(result)
               System.out.println(Thread.currentThread().getName()+"\\t 插入队列"+data+"成功");
           else
               System.out.println(Thread.currentThread().getName()+"\\t 插入队列"+data+"失败");
           
           TimeUnit.SECONDS.sleep(1);
        
        System.out.println("生产结束");

    

    //消费方法
    public void myConsumer() throws InterruptedException 

        String rs=null;

        while (FLAG)
             rs = blockingQueue.poll(2L, TimeUnit.SECONDS);

             if (rs==null||rs.equalsIgnoreCase(""))
             
                 FLAG=false;
                 System.out.println(Thread.currentThread().getName()+"超过两秒钟没取到商品，退出");
                 System.out.println();
                 System.out.println();
                 System.out.println();
                 return;  //
             
            System.out.println(Thread.currentThread().getName()+"\\t 消费队列"+rs+"成功");
        

    


    public  void stop()
        this.FLAG=false;