await/signal/lock实现生产消费者模式

最新推荐文章于 2025-02-23 19:26:42 发布

原创最新推荐文章于 2025-02-23 19:26:42 发布 · 520 阅读

0 ·

CC 4.0 BY-SA版权

JAVA并发包专栏收录该内容

12 篇文章

订阅专栏

本文深入探讨了使用多线程实现生产者与消费者模式，详细介绍了如何通过并发控制来确保资源的有效分配与管理。通过实例展示了如何利用Java中的并发工具，如Lock、Condition等，实现生产者线程将资源添加到缓冲区，并在消费者线程从缓冲区获取资源时进行同步，从而有效避免了资源竞争和死锁等问题。

存储类GoodStorage：

package main.wll.fish.product;

import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;

public class GoodStorage {
	private static final int SIZE = 2;
	private List<Good> storage = new ArrayList<Good>(SIZE);

	// 锁
	private final Lock lock = new ReentrantLock();
	// 仓库满的条件变量
	private final Condition full = lock.newCondition();

	// 仓库空的条件变量
	private final Condition empty = lock.newCondition();

	public void add(Good good) {
		lock.lock();
		{
			while (storage.size() >= SIZE) {
				try {
					System.out.println(Thread.currentThread().getName() + "------>product wait.... now ListSIze:"
							+ storage.size());
					full.await();
				} catch (InterruptedException e) {
					e.printStackTrace();
				}
			}

			storage.add(good);
			System.out.println(Thread.currentThread().getName() + "------>product :" + good.toString()
					+ ", now ListSIze:" + storage.size());

			empty.signalAll();
		}
		lock.unlock();
	}

	public void remove() {
		lock.lock();
		{
			while (storage.size() == 0) {
				try {
					System.out.println(Thread.currentThread().getName() + "------>consume wait....  now ListSIze:"
							+ storage.size());
					empty.await();
				} catch (InterruptedException e) {
					e.printStackTrace();
				}
			}

			Good good = storage.get(0);
			storage.remove(0);
			System.out.println(Thread.currentThread().getName() + "------------------------------------>consume :"
					+ good.toString() + ", now ListSIze:" + storage.size());

			full.signalAll();
			
		}
		lock.unlock();
	}

}

class Good {
	public long id;

	public Good(long id) {
		this.id = id;
	}

	public String toString() {
		return String.format("Good-%d", this.id);
	}
}

生产者：

[java] view plain copy print ?

import java.util.Random;
import java.util.concurrent.atomic.AtomicInteger;
class Producter implements Runnable {
private static AtomicInteger ato = new AtomicInteger(0);
private GoodStorage store;
public Producter(GoodStorage store ){
this.store = store;
}
public void run() {
while(true){
try {
Thread.currentThread().sleep(new Random().nextInt(1000));
// queue.put(new Good(System.currentTimeMillis()));
store.add(new Good(ato.incrementAndGet()));
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}

消费者：

[java] view plain copy print ?

import java.util.Random;
class Consumer implements Runnable {
private GoodStorage store;
public Consumer(GoodStorage store ){
this.store = store;
}
public void run() {
while(true){
try {
Thread.currentThread().sleep(new Random().nextInt(1000));
store.remove();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}

运行主类：

[java] view plain copy print ?

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
public class Main {
static ExecutorService pool = Executors.newCachedThreadPool();
public static void main(String[] args) {
GoodStorage store = new GoodStorage();
pool.execute(new Producter(store));
pool.execute(new Producter(store));
pool.execute(new Producter(store));
pool.execute(new Consumer(store));
pool.execute(new Consumer(store));
}
}

运行结果：

pool-1-thread-8------>product wait.... now ListSIze:2
pool-1-thread-12------>product wait.... now ListSIze:2
pool-1-thread-1------>product wait.... now ListSIze:2
pool-1-thread-7------>product wait.... now ListSIze:2
pool-1-thread-13------>product wait.... now ListSIze:2
pool-1-thread-9------>product wait.... now ListSIze:2
pool-1-thread-17------>product wait.... now ListSIze:2
pool-1-thread-16------>product wait.... now ListSIze:2
pool-1-thread-5------>product wait.... now ListSIze:2
pool-1-thread-20------------------------------------>consume :Good-34532, now ListSIze:1
pool-1-thread-20------------------------------------>consume :Good-34533, now ListSIze:0
pool-1-thread-20------>consume wait....  now ListSIze:0
pool-1-thread-21------>consume wait....  now ListSIze:0
pool-1-thread-6------>product :Good-34534, now ListSIze:1
pool-1-thread-6------>product :Good-34535, now ListSIze:2
pool-1-thread-6------>product wait.... now ListSIze:2
pool-1-thread-10------>product wait.... now ListSIze:2
pool-1-thread-2------>product wait.... now ListSIze:2
pool-1-thread-14------>product wait.... now ListSIze:2
pool-1-thread-18------>product wait.... now ListSIze:2
pool-1-thread-3------>product wait.... now ListSIze:2
pool-1-thread-11------>product wait.... now ListSIze:2
pool-1-thread-15------>product wait.... now ListSIze:2
pool-1-thread-19------>product wait.... now ListSIze:2
pool-1-thread-4------>product wait.... now ListSIze:2
pool-1-thread-8------>product wait.... now ListSIze:2
pool-1-thread-12------>product wait.... now ListSIze:2
pool-1-thread-1------>product wait.... now ListSIze:2
pool-1-thread-7------>product wait.... now ListSIze:2
pool-1-thread-13------>product wait.... now ListSIze:2
pool-1-thread-9------>product wait.... now ListSIze:2
pool-1-thread-17------>product wait.... now ListSIze:2
pool-1-thread-16------>product wait.... now ListSIze:2
pool-1-thread-5------>product wait.... now ListSIze:2
pool-1-thread-20------------------------------------>consume :Good-34534, now ListSIze:1
pool-1-thread-20------------------------------------>consume :Good-34535, now ListSIze:0
pool-1-thread-20------>consume wait....  now ListSIze:0
pool-1-thread-21------>consume wait....  now ListSIze:0