【并发编程】生产者-消费者模式

2022-10-25 15:23:45 浏览数 (2)

生产者和消费者也是一个非常经典的多线程模式 在生产-消费模式中:通常由两类线程 即若干生产者的线程和若干消费者的线程。生产者线程负责提交用户请求 消费者线程负责具体处理生产者提交的人 在生产者和消费者之间通过共享内存缓存区进行通信。

生产者消费者例子: Data类:

代码语言:javascript复制
public final class Data {

	private String id;
	private String name;
	
	public Data(String id, String name){
		this.id = id;
		this.name = name;
	}
	
	public String getId() {
		return id;
	}

	public void setId(String id) {
		this.id = id;
	}

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	@Override
	public String toString(){
		return "{id: "   id   ", name: "   name   "}";
	}
	
}

Provider 类:

代码语言:javascript复制
import java.util.Random;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicInteger;

public class Provider implements Runnable{
	
	//共享缓存区
	private BlockingQueue<Data> queue;
	//多线程间是否启动变量,有强制从主内存中刷新的功能。即时返回线程的状态
	private volatile boolean isRunning = true;
	//id生成器
	private static AtomicInteger count = new AtomicInteger();
	//随机对象
	private static Random r = new Random(); 
	
	public Provider(BlockingQueue queue){
		this.queue = queue;
	}

	@Override
	public void run() {
		while(isRunning){
			try {
				//随机休眠0 - 1000 毫秒 表示获取数据(产生数据的耗时) 
				Thread.sleep(r.nextInt(1000));
				//获取的数据进行累计...
				int id = count.incrementAndGet();
				//比如通过一个getData方法获取了
				Data data = new Data(Integer.toString(id), "数据"   id);
				System.out.println("当前线程:"   Thread.currentThread().getName()   ", 获取了数据,id为:"   id   ", 进行装载到公共缓冲区中...");
				//添加数据  在2秒中添加不了返回false
				if(!this.queue.offer(data, 2, TimeUnit.SECONDS)){
					System.out.println("提交缓冲区数据失败....");
					//do something... 比如重新提交
				}
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
		}
	}
	
	public void stop(){
		this.isRunning = false;
	}
	
}

Consumer 类:

代码语言:javascript复制
import java.util.Random;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.TimeUnit;

public class Consumer implements Runnable{

	private BlockingQueue<Data> queue;
	
	public Consumer(BlockingQueue queue){
		this.queue = queue;
	}
	
	//随机对象
	private static Random r = new Random(); 

	@Override
	public void run() {
		while(true){
			try {
				//获取数据
				Data data = this.queue.take();
				//进行数据处理。休眠0 - 1000毫秒模拟耗时
				Thread.sleep(r.nextInt(1000));
				System.out.println("当前消费线程:"   Thread.currentThread().getName()   ", 消费成功,消费数据为id: "   data.getId());
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
		}
	}
}

Main 类:

代码语言:javascript复制
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.LinkedBlockingQueue;

public class Main {

	public static void main(String[] args) throws Exception {
		//内存缓冲区
		BlockingQueue<Data> queue = new LinkedBlockingQueue<Data>(10);
		//生产者
		Provider p1 = new Provider(queue);
		
		Provider p2 = new Provider(queue);
		Provider p3 = new Provider(queue);
		//消费者
		Consumer c1 = new Consumer(queue);
		Consumer c2 = new Consumer(queue);
		Consumer c3 = new Consumer(queue);
		//创建线程池运行,这是一个缓存的线程池,可以创建无穷大的线程,没有任务的时候不创建线程。空闲线程存活时间为60s(默认值)

		ExecutorService cachePool = Executors.newCachedThreadPool();
		cachePool.execute(p1);
		cachePool.execute(p2);
		cachePool.execute(p3);
		cachePool.execute(c1);
		cachePool.execute(c2);
		cachePool.execute(c3);

		try {
			Thread.sleep(3000);
		} catch (InterruptedException e) {
			e.printStackTrace();
		}
		p1.stop();
		p2.stop();
		p3.stop();
		try {
			Thread.sleep(2000);
		} catch (InterruptedException e) {
			e.printStackTrace();
		}		
//		cachePool.shutdown(); 
//		cachePool.shutdownNow();
		

	}
	
}

运行结果:

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