阻塞队列

2019-03-07  本文已影响0人  暖熊熊

关键方法,
put和take
这俩个方法在入队列的时候如果队列已满,就会等待队列有了空位置再入,出队的时候如果队列为空就会阻塞等待队列有了值再出。

package com.ghw.springboot.A0307;

import java.util.Random;
import java.util.concurrent.*;
import java.util.concurrent.atomic.AtomicInteger;

/**
 * 阻塞队列测试
 */
public class BlockingQueueTest {

    public static void main(String[] args) throws InterruptedException {
        // 声明一个容量为5的缓存队列
        BlockingQueue<String> queue = new LinkedBlockingQueue<>(5);

        Producer producer1 = new Producer(queue);
        Producer producer2 = new Producer(queue);
        Producer producer3 = new Producer(queue);
        Consumer consumer = new Consumer(queue);

        // 借助Executors
        ExecutorService service = Executors.newCachedThreadPool();
        // 启动线程
        service.execute(producer1);
        service.execute(producer2);
        service.execute(producer3);
        service.execute(consumer);

        // 执行3s
        Thread.sleep(3 * 1000);
        producer1.stop();
        producer2.stop();
        producer3.stop();

        Thread.sleep(2000);
        // 退出Executor
        service.shutdown();
    }
}

class Consumer implements Runnable {

    private BlockingQueue<String> queue;
    private static final int DEFAULT_RANGE_FOR_SLEEP = 1000;

    public Consumer(BlockingQueue<String> queue) {
        this.queue = queue;
    }

    @Override
    public void run() {
        System.out.println("启动消费者线程!" + Thread.currentThread().getName());
        Random r = new Random();
        boolean isRunning = true;
        try {
            while (true) {
                System.out.println("队列:" + queue + "队列大小:" + queue.size());
                String data = queue.take();
                System.out.println("正在消费数据:" + data);
                TimeUnit.MILLISECONDS.sleep(r.nextInt(DEFAULT_RANGE_FOR_SLEEP));
            }
        } catch (InterruptedException e) {
            e.printStackTrace();
            Thread.currentThread().interrupt();
        } finally {
            System.out.println("退出消费者线程!");
        }
    }


}

class Producer implements Runnable {

    private volatile boolean isRunning = true;
    private BlockingQueue queue;
    private static AtomicInteger count = new AtomicInteger();
    private static final int DEFAULT_RANGE_FOR_SLEEP = 1000;

    public Producer(BlockingQueue queue) {
        this.queue = queue;
    }

    @Override
    public void run() {
        String data;
        Random r = new Random();

        System.out.println("启动生产者线程!" + Thread.currentThread().getName());
        try {
            while (isRunning) {
                TimeUnit.MILLISECONDS.sleep(r.nextInt(DEFAULT_RANGE_FOR_SLEEP));
                data = "data:" + count.incrementAndGet();
                System.out.println(data + "入队");
                queue.put(data);
            }
        } catch (InterruptedException e) {
            e.printStackTrace();
            Thread.currentThread().interrupt();
        } finally {
            System.out.println("退出生产者线程!");
        }
    }

    public void stop() {
        isRunning = false;
    }
}

运行结果:

启动生产者线程!pool-1-thread-2
启动消费者线程!pool-1-thread-4
队列:[]队列大小:0
启动生产者线程!pool-1-thread-1
启动生产者线程!pool-1-thread-3
data:1入队
正在消费数据:data:1
队列:[]队列大小:0
data:2入队
正在消费数据:data:2
data:3入队
data:4入队
data:5入队
队列:[data:3, data:4, data:5]队列大小:3
正在消费数据:data:3
data:6入队
data:7入队
data:8入队
data:9入队
队列:[data:4, data:5, data:6, data:7, data:8]队列大小:5
正在消费数据:data:4
data:10入队
data:11入队
data:12入队
队列:[data:5, data:6, data:7, data:8, data:9]队列大小:5
正在消费数据:data:5
data:13入队
队列:[data:6, data:7, data:8, data:9, data:10]队列大小:5
正在消费数据:data:6
队列:[data:7, data:8, data:9, data:10, data:11]队列大小:5
退出生产者线程!
正在消费数据:data:7
data:14入队
队列:[data:8, data:9, data:10, data:11, data:12]队列大小:5
正在消费数据:data:8
退出生产者线程!
队列:[data:9, data:10, data:11, data:12, data:13]队列大小:5
正在消费数据:data:9
退出生产者线程!
队列:[data:10, data:11, data:12, data:13, data:14]队列大小:5
正在消费数据:data:10
队列:[data:11, data:12, data:13, data:14]队列大小:4
正在消费数据:data:11
队列:[data:12, data:13, data:14]队列大小:3
正在消费数据:data:12
队列:[data:13, data:14]队列大小:2
正在消费数据:data:13
队列:[data:14]队列大小:1
正在消费数据:data:14
队列:[]队列大小:0

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