使用ConcurrentLinkedQueue惨痛的教训【转】

 1 import java.util.concurrent.ConcurrentLinkedQueue;
 2 import java.util.concurrent.CountDownLatch;
 3 import java.util.concurrent.ExecutorService;
 4 import java.util.concurrent.Executors;
 5 
 6 public class ConcurrentLinkedQueueTest {
 7     
 8     private static ConcurrentLinkedQueue<Integer> queue = new ConcurrentLinkedQueue<Integer>();
 9     
10     private static int count = 100000;
11     
12     private static int count2 = 2; // 线程个数
13     
14     private static CountDownLatch cd = new CountDownLatch(count2);
15     
16     public static void dothis() {
17         for (int i = 0; i < count; i++) {
18             queue.offer(i);
19         }
20     }
21     
22     public static void main(String[] args) throws InterruptedException {
23         long timeStart = System.currentTimeMillis();
24         ExecutorService es = Executors.newFixedThreadPool(4);
25         ConcurrentLinkedQueueTest.dothis();
26         for (int i = 0; i < count2; i++) {
27             es.submit(new Poll());
28         }
29         cd.await();
30         System.out.println("cost time " + (System.currentTimeMillis() - timeStart) + "ms");
31         es.shutdown();
32     }
33     
34     static class Poll implements Runnable {
35         @Override
36         public void run() {
37             //while (queue.size() > 0) {    // 效率低，每次都需要计算整个队列的个数
38             while (!queue.isEmpty()) {
39                 System.out.println(queue.poll());
40             }
41             cd.countDown();
42         }
43     }
44 }