Scanner.hasNext（）返回false [英] Scanner.hasNext() returns false

问题描述

我的目录中包含许多文件 - 每个文件都包含800多行。 Hovewer，当我尝试使用Scanner读取它时，它似乎是空的。

I have directory with many files in it - each with over 800 lines in it. Hovewer, when I try to read it using Scanner, it seems empty.

File f1 = new File("data/cityDistances/a.txt"),
     f2 = new File("data/cityDistances/b.txt");
System.out.println(f1.exists() && f2.exists()); //return true
System.out.println(f1.getTotalSpace() > 0 && f2.getTotalSpace() > 0); //return true
Scanner in = new Scanner(f1);
System.out.println(in.hasNext()); // return false;
System.out.println(in.hasNextLine()); //return false;

为什么它会像那样？

我已经设法使用 BufferedReader 来完成。但是，似乎更奇怪的是 BufferedReader 有效，扫描器没有。

I've managed to do it using BufferedReader. Nonetheless, it seems even more strange that BufferedReader works and Scanner didn't.

推荐答案

由于Scanner的默认分隔符是空白，这意味着您的 a.txt 仅包含空格 - 它有800行空白吗？ ;）

As the default delimeter for Scanner is whitespace, that would imply your a.txt contains only whitespace - does it have 800 lines of whitespace? ;)

您是否尝试过以下操作？

Have you tried the following?

new Scanner(new BufferedReader(new FileReader("a.txt")));

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