20 使用Lock和Condition来实现生产者消费者

快来打我* 2024-04-18 17:47 13阅读 0赞

对比两种方式，Condition的方式可以更加精确的指定哪些线程被唤醒。

public class MyContainer2<T> {
    	final private LinkedList<T> lists = new LinkedList<>();
    	final private int MAX = 10; //最多10个元素
    	private int count = 0;
    	
    	private Lock lock = new ReentrantLock();
    	//生产者的条件
    	private Condition producer = lock.newCondition();
    	//消费者的条件
    	private Condition consumer = lock.newCondition();
    	
    	public void put(T t) {
    		try {
    			lock.lock();
    			while(lists.size() == MAX) { //想想为什么用while而不是用if？
    				producer.await();
    			}
    			
    			lists.add(t);
    			++count;
    			consumer.signalAll(); //通知消费者线程进行消费
    		} catch (InterruptedException e) {
    			e.printStackTrace();
    		} finally {
    			lock.unlock();
    		}
    	}
    	
    	public T get() {
    		T t = null;
    		try {
    			lock.lock();
    			while(lists.size() == 0) {
    				consumer.await();
    			}
    			t = lists.removeFirst();
    			count --;
    			producer.signalAll(); //通知生产者进行生产
    		} catch (InterruptedException e) {
    			e.printStackTrace();
    		} finally {
    			lock.unlock();
    		}
    		return t;
    	}
    	
    	public static void main(String[] args) {
    		MyContainer2<String> c = new MyContainer2<>();
    		//启动消费者线程
    		for(int i=0; i<10; i++) {
    			new Thread(()->{
    				for(int j=0; j<5; j++) System.out.println(c.get());
    			}, "c" + i).start();
    		}
    		
    		try {
    			TimeUnit.SECONDS.sleep(2);
    		} catch (InterruptedException e) {
    			e.printStackTrace();
    		}
    		
    		//启动生产者线程
    		for(int i=0; i<2; i++) {
    			new Thread(()->{
    				for(int j=0; j<25; j++) c.put(Thread.currentThread().getName() + " " + j);
    			}, "p" + i).start();
    		}
    	}
    }

转载于:https://my.oschina.net/u/4131327/blog/3075317