是否可以使用一行将流收集到两个不同的集合中？ [英] Is it possible to collect a stream to two different collections using one line?

问题描述

我有以下代码:(为了简洁而简化）

I have the following code: (simplified for bravity)

public void search(Predicate<String> predicate, Elements elements)
{
    List<SearchResult> searchResults = elements.stream()
        .filter(element -> predicate.test(element.ownText()))
        .map(element -> new SearchResult(element.ownText(), element.baseUri(),element.tagName()))
        .collect(Collectors.toList());
}

但是现在，我想要另一个包含所有已过滤元素的列表映射。
是否可以使用流来实现，或者我应该更改为foreach循环？

But now, I want to have another list which would contain all filtered elements without the mapping. Is it possible to do that with a stream, or should I change to a foreach loop for that?

推荐答案

您可以在过滤后收集元素，然后使用此列表将元素映射到搜索结果：

You can collect the elements after filtering and then use this list to map the elements to search results:

public void search(Predicate<String> predicate, Elements elements) {
    List<Element> filteredElements = 
        elements.stream()
                .filter(element -> predicate.test(element.ownText()))
                .collect(Collectors.toList());

    List<SearchResult> searchResults = 
        filteredElements.stream()
                        .map(element -> new SearchResult(element.ownText(),element.baseUri(),element.tagName()))
                        .collect(Collectors.toList());
}

这不会比其他答案的解决方案花费更多时间，但不会没有副作用，线程安全，易于阅读和理解。

This won't take more time than the solutions of the other answers but doesn't have side effects, is thread safe as well as easy to read and understand.

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