java-并发集合-阻塞队列 LinkedBlockingQueue 演示

java-并发集合-阻塞队列 LinkedBlockingQueue 演示

package me.grass.demo.concuronte;


import java.util.Date;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.Executors;


/**
 * 阻塞队列 java.util.concurrent.LinkedBlockingQueue 使用
 * 阻塞队列提供两组入队、出队方法，分别为：
 * 无阻塞：add();poll();
 * 阻塞：put();take();
 */
public class LinkedBlockingQueueDemo {
  /**
   * 生产慢，消费快，导致队里阻塞
   * @param args
   * @throws InterruptedException
   *  @author xxj  
   */
  public static void main(String[] args) throws InterruptedException {
    /*测试逻辑：
     * 1.阻塞队列固定大小50，100个线程写入将产生写入阻塞
     * 2.消费者比生产者快，消费时会产生读取阻塞
     * */
    Date before=new Date();
    int pTotalThread =100; //最大线程数（生产者）
    int pActivities=5; //最大线程数（生产者）
    int cTotalThread =100; //活动线程数（消费者）
    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："+_blockingQueue.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;
  /**
   * 阻塞队列，队列固定大小50，100个线程写入将产生写入阻塞
   */
  static java.util.concurrent.LinkedBlockingQueue<Integer> _blockingQueue = 
      new java.util.concurrent.LinkedBlockingQueue<Integer>(50);
      
  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() {
      try {
        //阻塞队列，使用 put 加入队列，如果队列满了将阻塞
        LinkedBlockingQueueDemo._blockingQueue.put(_key);//生产
        System.out.println("已创建："+_key);
        Thread.sleep(1000);//让生产慢点儿
      } catch (InterruptedException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
      }
      LinkedBlockingQueueDemo._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
      try {
        //阻塞队列使用 take() 产生阻塞 ，并发队列使用 poll()
        Integer nInteger = LinkedBlockingQueueDemo._blockingQueue.take();//消费         
        System.err.println("消费："+nInteger);
        Thread.sleep(100);//每次消费等一会儿
      } catch (InterruptedException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
      }
      LinkedBlockingQueueDemo._lCountDownLatch.countDown();//线程同步递减
    }
  }
}