如何在Java中将扫描仪字符串转换为Stream？ [英] How to make scanner strings into a Stream in Java?

问题描述

在 Java8 中，我如何形成 String 扫描仪读取结果？

In Java8, how can I form a Stream of String out of the scanner read results?

InputStream is = A.class.getResourceAsStream("data.txt");
Scanner scanner = new Scanner(new BufferedInputStream(is), "UTF-8");
while (scanner.hasNextLine()) {
    System.out.println(scanner.nextLine());
}

这是将扫描程序转换为我想要使用 forEach 。

That is turn a scanner into a stream which I would like to iterate using forEach.

推荐答案

你这一切都错了，没有扫描仪是必需的：

You are going about this all wrong, no Scanner is required:

try (final InputStream is = A.class.getResourceAsStream("data.txt");
        final Reader r = new InputStreamReader(is, StandardCharsets.UTF_8);
        final BufferedReader br = new BufferedReader(r);
        final Stream<String> lines = br.lines()) {

}

如果你真的想要使用扫描仪然后它实现Iterator 所以你可以这样做：

If you really want to use a Scanner then it implements Iterator so you can just do:

public Stream<String> streamScanner(final Scanner scanner) {
    final Spliterator<String> splt = Spliterators.spliterator(scanner, Long.MAX_VALUE, Spliterator.ORDERED | Spliterator.NONNULL);
    return StreamSupport.stream(splt, false)
            .onClose(scanner::close);
}

P.S。你似乎也没有关闭资源。 始终关闭 InputStream 。

P.S. you also don't seem to be closing resources. always close an InputStream.

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