java blockingqueue 单独用, 结合线程池用

LinkedBlockingQueue 顾名思义就是link 链表实现，queue就是队列，入队出队，blocking不用管，

所以他就是一个队列，把他当成queue用就行。over

单独用代码:

package ThreadPoolTest;

import java.util.concurrent.BlockingQueue;
import java.util.concurrent.LinkedBlockingDeque;
import java.util.concurrent.LinkedBlockingQueue;

/**
 * 
 * @category 阻塞队列BlockQueue,共四种, 本文说的是单独的 blockQueue 用于生产者消费者问题,
 * ArrayBlockingQueue
 * LinkedBlockingQueue
 * PriorityBlockingQueue
 * SynchronousQueue
 * @author jaloli
 * 
 * result
 *  Producer: producer:0
	Producer: producer:1
	Producer: producer:3
	Producer: producer:2
	Consumer:producer:3
	Consumer:producer:2
	Consumer:producer:0
	Consumer:producer:1
	Producer: producer:4
	Consumer:producer:4
	由result 的system.out可看出这些输出不具有参考性, LinkedBlockingDeque的固定容量2,在结果中无法体现,所以多线程中BlockingQueue结合线程池用比较好
 *
 */

public class BlockQueueTest {
	
	
	public static void main(String[] args) throws InterruptedException {
		//可以看出放进去一个, bq 中有一个
		BlockingQueue bq = new LinkedBlockingQueue(2);//这个参数是blockingqueue 固定的容量
//		bq.put(String.valueOf(1));
//		System.out.println("Producer: "+1+" bq.size(): "+bq.toString());
//		bq.put(String.valueOf(2));
//		System.out.println("Producer: "+2+" bq.size(): "+bq.toString());
		
		for(int i=0;i<5;i++){
			Producer producer = new Producer(bq,i);
			Consumer consumer = new Consumer(bq);
			new Thread(producer).start();//第二个参数是线程名
			new Thread(consumer).start();
		}
	}

}

class Producer implements Runnable {
	
	private BlockingQueue bq;
	private int productid;
	
	public Producer(int productid) {
		super();
		this.productid = productid;
	}
	
	public Producer(BlockingQueue bq,int productid) {
		super();
		this.bq = bq;
		this.productid = productid;
	}
	
	@Override
	public void run() {
		try {Thread.sleep(1000);
			bq.put(String.valueOf(productid));
			System.out.println("Producer: "+productid+" bq.size(): "+bq.toString());
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
}

class Consumer implements Runnable{
	private BlockingQueue bq;
	
	public Consumer() {
		super();
	}
	
	public Consumer(BlockingQueue bq) {
		super();
		this.bq = bq;
	}

	@Override
	public void run() {
		try {
			String temp = bq.take();
			System.out.println("Consumer: "+temp+" bq.size(): "+bq.size());
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
	
}

线程池的Executors.newFixedThreadPool(3) 是线程池有3个线程, 但是如果来100个任务,且单个任务执行特别慢, 那么会因为来不及执行剩下的97个任务而产生丢任务, 

所以需要有一个blockingqueue队列来保存线程池暂时来不及执行的runnable task, 这个blockingqueue 也是有大小限制的,代码如下:

结合线程池用代码:

package ThreadPoolTest;

import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.SynchronousQueue;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;

public class ThreadPoolAndBlockQueue {

	//线程池不自带blockqueue的用法
	public void notContainBQ(){
		BlockingQueue queue = new LinkedBlockingQueue(3);
		ExecutorService service = Executors.newCachedThreadPool();
		Producer producer; 
		Consumer consumer;
		for(int i=0;i<5;i++) {
			producer = new Producer(queue,i);
			consumer = new Consumer(queue);
			service.execute(producer);
			service.execute(consumer);
		}
	}
	
	//自带blockqueue的用法
	public static void containBQ() {
		ExecutorService service = new ThreadPoolExecutor(0, Integer.MAX_VALUE, 60L, 
				TimeUnit.SECONDS, new LinkedBlockingQueue(2));//这个bq参数是控制execute提交过来后,真正执行的线程数的
								  //如果一个任务过程,迟迟执行不完, 导致过来的runnable任务太多,blockqueue放不下,那么会丢runnable任务
		Producer producer; 
		Consumer consumer;
		BlockingQueue bq = new LinkedBlockingQueue(2);
		producer = new Producer(bq,1);
//		consumer = new Consumer(bq);
		for(int i=0;i<105;i++) {
			service.execute(producer);
//			service.execute(consumer);
		}
		
	}
	
	
	public static void main(String[] args) {
		containBQ();
	}

}