一個使用Java BlockingQueue實現的生產者和消費者

消費者

package consumer;

import java.util.concurrent.BlockingQueue;
import java.util.concurrent.TimeUnit;


public class Consumer implements Runnable {

	/*
	 * 用util.concurrent.BlockingQueue溝通生產者和消費者的橋樑
	*/
	BlockingQueue<String> queue;
	String id;
	@SuppressWarnings("unused")
	private volatile boolean      isRunning               = true;
	public Consumer(BlockingQueue<String> queue, String id) {
        this.queue = queue;
        this.id = id;
    }
	
    public void stop() {
        isRunning = false;
    }
    
	@Override
	public void run() {
		System.out.println("Thread: " + id + " Consumer thread is running...");
        boolean isRunning = true;
        try {
            while (isRunning) {
                System.out.println("Thread: " + id + " fetch data from linkedQueue..." + " queue size: " + queue.size());
                /*
                 * 從隊列裏取出一個元素，2秒超時，如果兩秒之後還沒有東西可以取，則poll返回null
                 */
                String data = queue.poll(2, TimeUnit.SECONDS);
                if (null != data) {
                    System.out.println("Thread: " + id + " has consumed one data from queue: " + data
                    		+ "   Queue sise: " + queue.size());
                    // simulate data consumption
                    Thread.sleep(1000);
                } else {
                    isRunning = false;
                    // 消費者準備退出
                    System.out.println("Thread: " + id + " Consumer read queue timeout");
                }
            }
        } catch (InterruptedException e) {
            e.printStackTrace();
            Thread.currentThread().interrupt();
        } finally {
            System.out.println("Thread: " + id + " consumer thread ends");
            
        }
	}

}

生產者

package consumer;

import java.util.concurrent.BlockingQueue;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicInteger;

public class Producer implements Runnable {
 
	BlockingQueue<String> queue;
	String id;
    public Producer(BlockingQueue<String> queue, String id) {
        this.queue = queue;
        this.id = id;
    }
 
    @Override
    public void run() {
        String data = null;
        
        try {
            while (isRunning) {
                System.out.println("PRODUCER: " + id + " is running");
                Thread.sleep(100);
 
                data = "data:" + count.incrementAndGet();
                System.out.println("Thread: " + id + " procedued data into queue: " + data + " ...");
                if (!queue.offer(data, 2, TimeUnit.SECONDS)) {
                    System.out.println("failed to put data into queue: " + data);
                }
            }
        } catch (InterruptedException e) {
            e.printStackTrace();
            Thread.currentThread().interrupt();
        } finally {
            System.out.println("Thread: " + id + " quit from producer thread");
        }
    }
 
    public void stop() {
        isRunning = false;
    }
 
    private volatile boolean      isRunning               = true;
    private static AtomicInteger  count                   = new AtomicInteger();
 
}

測試代碼

package consumer;

import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.LinkedBlockingQueue;

public class ConsumerProducerTest {
 
    public static void main(String[] args) throws InterruptedException {

        BlockingQueue<String> queue = new LinkedBlockingQueue<String>(15);
 
        Producer producer1 = new Producer(queue, "PROD1");
        Producer producer2 = new Producer(queue, "PROD2");
        Producer producer3 = new Producer(queue, "PROD3");
        Consumer consumer1 = new Consumer(queue, "CONSUMER1");
        Consumer consumer2 = new Consumer(queue, "CONSUMER2");
 
        ExecutorService service = Executors.newCachedThreadPool();
        
        service.execute(producer1);
        service.execute(producer2);
        service.execute(producer3);
        service.execute(consumer1);
        service.execute(consumer2);
 
        Thread.sleep(3 * 1000);
        producer1.stop(); // 一定要先關閉生產者
        producer2.stop();
        producer3.stop();
        consumer1.stop();
        consumer2.stop();
 
        Thread.sleep(2000);

        service.shutdown();
    }
}