如何将流的元素收集到队列中？[重复]

Question

我有以下代码:

Queue<Reward> possibleRewards = 
    Stream.of(Reward.values())
          .flatMap(reward -> IntStream.range(0, reward.getOccurencies()).mapToObj(i -> reward))
          .collect(Collectors.toList());

如您所见，我需要将< code >流的元素收集到< code >队列中，而不是< code >列表中。但是，没有< code > collectors . to queue()方法。如何将元素收集到< code >队列中？

Answer 1

Queue<Reward> possibleRewards = new LinkedBlockingQueue<>(); //Or whichever type of queue you would like
possibleRewards.addAll(Stream.of(Reward.values())
    .flatMap(reward -> IntStream.range(0, reward.getOccurencies()).mapToObj(i -> reward))
    .collect(Collectors.toList()));

Answer 2

您可以使用收集器.to收集（），它允许您选择要生成的任何集合实现：

Queue<Reward> possibleRewards = 
    Stream.of(Reward.values())
          .flatMap(reward -> IntStream.range(0, reward.getOccurencies()).mapToObj(i -> reward))
          .collect(Collectors.toCollection(PriorityQueue::new)); // use whatever Queue 
                                                                 // implementation you want