java blockingqueue 单独用, 结合线程池用

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:0Producer: producer:1Producer: producer:3Producer: producer:2Consumer:producer:3Consumer:producer:2Consumer:producer:0Consumer:producer:1Producer: producer:4Consumer: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<String> bq = new LinkedBlockingQueue<String>(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<String> bq;private int productid;public Producer(int productid) {super();this.productid = productid;}public Producer(BlockingQueue<String> bq,int productid) {super();this.bq = bq;this.productid = productid;}@Overridepublic 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<String> bq;public Consumer() {super();}public Consumer(BlockingQueue<String> bq) {super();this.bq = bq;}@Overridepublic 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<String> queue = new LinkedBlockingQueue<String>(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<Runnable>(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<String> bq = new LinkedBlockingQueue<String>(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();}}