java-并发集合-并发队列 ConcurrentLinkedQueue 演示

java-并发集合-并发队列 ConcurrentLinkedQueue 演示


目标：模拟 5 个线程同时并发读取“并发队列”，并使用 CountDownLatch 类协助计算消费耗时。

package me.grass.demo.concuronte;


import java.util.Date;


/**
 * 同步队列 java.util.concurrent.ConcurrentLinkedQueue 使用
 * 
 */
public class ConcurrentLinkedQueueDemo {
  /**
   * 生产者快，消费者慢
   * @param args
   * @throws InterruptedException
   *  @author xxj
   */
  public static void main(String[] args) throws InterruptedException {
    LinkedBlockingQueueDemo._lCountDownLatch.countDown();
    Date before=new Date();
    int pTotalThread =100; //最大线程数（生产者）
    int cTotalThread =5; //活动线程数（消费者）
    int pActivities=50; //最大线程数（生产者）
    int cActivities=5; //活动线程数（消费者）
    _lCountDownLatch = new CountDownLatch(pTotalThread+cTotalThread);
    
    startProducer(pActivities,pTotalThread);
    startConsumer(cActivities,cTotalThread);
    
    _lCountDownLatch.await();//等待所有线程完成
    Date after = new Date();


    System.out.println("队列为空："+_queue.isEmpty());
    System.out.println("耗时："+((after.getTime()-before.getTime())/1000));
    System.out.println("同步队列："+_lCountDownLatch.getCount());    
  }
  static java.util.concurrent.CountDownLatch _lCountDownLatch;
  static java.util.concurrent.ConcurrentLinkedQueue<Integer> _queue = 
      new ConcurrentLinkedQueue<Integer>();
      
  static void startProducer(int active,int totalThread) throws InterruptedException{
    java.util.concurrent.ExecutorService pool = Executors.newFixedThreadPool(active);
    int size =1024*1024*10;//产生 3 M 数据
    Thread thread ;
    for(int i=0;i<totalThread;i++){
      thread = new Thread(new producer(i,size));
      pool.execute(thread);
    }
  }
  static void startConsumer(int active,int totalThread) throws InterruptedException{
    java.util.concurrent.ExecutorService pool = Executors.newFixedThreadPool(active);    
    Thread thread ;
    //启动x个消费者
    for(int i=0;i<totalThread;i++){
      thread = new Thread(new consumer());
      pool.execute(thread);
    }
  }
  /**
   * 生产者
   * @author xxj 
   *
   */
  static class producer implements Runnable{
    public producer(int key,int size){
      _size=size;
      _key=key;
    }
    int _key;
    int _size;
    public void run() {
      ConcurrentLinkedQueueDemo._queue.add(_key);//生产
      System.out.println("已创建："+_key);
      ConcurrentLinkedQueueDemo._lCountDownLatch.countDown();//线程同步递减
    }
  }
  /**
   * 消费者
   * @author xxj
   *
   */
  static class consumer implements Runnable{
    public consumer(){
    }
    public void run() {
      //循环消费，直到队列内容为空
      while(!ConcurrentLinkedQueueDemo._queue.isEmpty()){
        Integer nInteger = ConcurrentLinkedQueueDemo._queue.poll();//消费
        System.err.println("消费："+nInteger);
        try {
          Thread.sleep(200);//每次消费等一会儿
        } catch (InterruptedException e) {
          // TODO Auto-generated catch block
          e.printStackTrace();
        }
      }
      ConcurrentLinkedQueueDemo._lCountDownLatch.countDown();//线程同步递减
    }
  }
}