多线程：生产者消费者模型

1、阻塞队列实现

public class Main {
    private static final int capacity=2, ptime=6, ctime=6;
    private static BlockingQueue<Integer> storage=new LinkedBlockingQueue<>(capacity);
    private static Integer count=0;
    static class Producer implements Runnable {
        @Override
        public void run() {
            for (int i = 0; i < ptime; i++) {
                try {
                    Thread.sleep(100);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                try {
		//这里上锁是为了保证put和打印是原子的，如果不需要打印，可以不上锁。
                    synchronized (count) {
                        storage.put(count);
                        System.out.println("Producer:" + Thread.currentThread().getName() + " put:  " + count++);
                    }
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }
    }
    static class Consumer implements Runnable {
        @Override
        public void run() {
            for (int i = 0; i < ctime; i++) {
                try {
                    Thread.sleep(100);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                try {
                        System.out.println("Consumer:" + Thread.currentThread().getName() + " take: " + storage.take());
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }
    }

    public static void main(String[] args) {
        new Thread(new Consumer(),"C1").start();
        new Thread(new Consumer(),"C2").start();
        new Thread(new Producer(),"P1").start();
        new Thread(new Producer(),"P2").start();
        new Thread(new Producer(),"P3").start();
    }
}

2、Synchronized实现

class Storage {
    final int storageSize;
    private int countNow = 0;
    Storage(int storageSize) {
        this.storageSize = storageSize;
    }
    public void produce() {
        System.out.print("Producer " + Thread.currentThread().getName());
        if (countNow < storageSize) {
            countNow++;
            System.out.print(" ##SUCCESS##, STORAGE:" + countNow);
        } else {
            System.out.print(" ##FAILTED:STORAGE FULL##");
        }
        System.out.println("   Producer==========================");
    }

    public void consume() {
        System.out.print("Consumer " + Thread.currentThread().getName());
        if (countNow > 0) {
            countNow--;
            System.out.println(" ##SUCCESS##, STORAGE:" + countNow);
        } else {
            System.out.println(" ##FAILTED: STORAGE EMPTY##");
        }
    }

    public int getCount(){
        return countNow;
    }
}

public class Main {
    private static Storage storage;
    static class Producer implements Runnable {
        @Override
        public void run() {
            for (int i = 0; i < storage.storageSize; i++) {
                synchronized (storage) {
                    storage.produce();
                    try {
                        Thread.sleep(10);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
            }
        }
    }

    static class Consumer implements Runnable {
        @Override
        public void run() {
            for (int i = 0; i < storage.storageSize; i++) {
                synchronized (storage) {
                    storage.consume();
                    try {
                        Thread.sleep(10);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
            }
        }
    }
    public static void main(String[] args) {
        storage=new Storage(10);
        new Thread(new Producer(),"P1").start();
        new Thread(new Producer(),"P2").start();
        new Thread(new Producer(),"P3").start();
        new Thread(new Consumer(),"C1").start();
        new Thread(new Consumer(),"C2").start();
    }
}

生产者和消费者都对同一仓库对象上锁。

3、ReentrantLock实现

4、信号量实现