java-并发集合-阻塞队列 LinkedBlockingQueue 演示

红太狼 2024-02-17 22:50 33阅读 0赞

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
    		}
    	}
    }