Scanner.hasNext() returns false

Question

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;

Why can it behave like that?

---

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

Solution 1

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

Have you tried the following?

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

Solution 2

I had a similar problem today reading a file with Scanner. I specified the encoding type of the file and it solved the problem.

scan = new Scanner(selectedFile,"ISO-8859-1");

Solution 3

This also happened to me today. I'm reading a plain text file from a Linux system written by some application in a Windows box and Scanner.hasNextLine() is always false even tough there are lines with the Windows line separator and all. As said by Hound Dog, by using

Scanner scanner = new Scanner(new BufferedReader(new FileReader(file))); 

it worked like a charm. FileReader or BufferedReader seem to properly identify and use some file characteristics.

Solution 4

Checking the scanner's exception may show that the file can't be read.

...
System.out.println(in.hasNext()); // return false;
IOException ex = in.ioException();
if (ex != null)
  ex.printStackTrace(System.out);
...

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Comments

[Achow]

This did the trick, though I am not sure why,my file was pretty huge, 19MB containing data(not whitespace), and it abruptly cut off when I was just using the scanner