@Testpublic void queuedemo(){ConcurrentLinkedQueue<Integer> queue = new ConcurrentLinkedQueue();for (int i = 0; i < 5; i++){queue.add(i);}//获取元素 不移除头结点for (int i =0; i < 3; i++){System.out.println("peek: " + queue.peek());}//返回在此队列元素上以恰当顺序进行迭代的迭代器Iterator<Integer> iterator = queue.iterator();while (iterator.hasNext()){System.out.println("iterator: " + iterator.next());}//获取元素并且在队列中移除，如果队列为空返回nullSystem.out.println("poll: " + queue.poll());//删除队首元素，如果队列为空返回NoSuchElementExceptionInteger remove = queue.remove();System.out.println("remove: " + remove);System.out.println(queue.peek());remove = queue.remove();System.out.println("remove: " + remove);System.out.println(queue.peek());}

控制台打印：

peek: 0
peek: 0
peek: 0
iterator: 0
iterator: 1
iterator: 2
iterator: 3
iterator: 4
poll: 0
remove: 1
2
remove: 2
3

Process finished with exit code 0