我正在寻找一种简洁的方法将一个 Iterator
转换为 Stream
,或者更具体地说,将迭代器视为流进行处理。
出于性能的考虑,我希望避免在新列表中复制迭代器:
Iterator<String> sourceIterator = Arrays.asList("A", "B", "C").iterator();
Collection<String> copyList = new ArrayList<String>();
sourceIterator.forEachRemaining(copyList::add);
Stream<String> targetStream = copyList.stream();
根据评论中的一些建议,我也尝试使用Stream.generate
:public static void main(String[] args) throws Exception {
Iterator<String> sourceIterator = Arrays.asList("A", "B", "C").iterator();
Stream<String> targetStream = Stream.generate(sourceIterator::next);
targetStream.forEach(System.out::println);
}
然而,我遇到了一个NoSuchElementException
(因为没有调用hasNext
)
Exception in thread "main" java.util.NoSuchElementException
at java.util.AbstractList$Itr.next(AbstractList.java:364)
at Main$$Lambda$1/1175962212.get(Unknown Source)
at java.util.stream.StreamSpliterators$InfiniteSupplyingSpliterator$OfRef.tryAdvance(StreamSpliterators.java:1351)
at java.util.Spliterator.forEachRemaining(Spliterator.java:326)
at java.util.stream.ReferencePipeline$Head.forEach(ReferencePipeline.java:580)
at Main.main(Main.java:20)
我查看了StreamSupport
和Collections
,但没有找到任何内容。
Stream.generate(iterator::next)
能行吗? - gontard