File size without opening the file

Question

Is there any way to determine a file's size without having to open it, as provided in the Java platform API (no 3rd party libs)? Also, I need the 64-bit size (which I assume Java would provide to begin with).

http://stackoverflow.com/questions/116574/java-get-file-size-efficiently — Anish Dasappan, Nov 03 '11 at 08:57

score 3 · Answer 1 · edited Nov 03 '11 at 08:48

3

Yes, calling .length() on a File Object will return its size in bytes.

edited Nov 03 '11 at 08:48

Bohemian

412,405
93
575
722

answered Nov 03 '11 at 08:48

Sahil Muthoo

12,033
2
29
38

That would require constructing an object first opening the file, though; or at least that's what I thought, correct? – Spliff Nov 03 '11 at 08:49
@Bohemian, Grammar Nazi! Just kidding, I was about to fix it myself. – Sahil Muthoo Nov 03 '11 at 08:49
Yes, you'll need a `new File(...)` for that. – Philipp Reichart Nov 03 '11 at 08:50
@Spliff A File object is an abstract pathname. Effectively it is a utility class that wraps a String. No file opening is required. – Nov 03 '11 at 08:51
@Spliff, There is no significant overhead in constructing a `File` Object. Java won't start reading the file contents when you call `new file()`. `.length()` returns the size reported by the file system. – Sahil Muthoo Nov 03 '11 at 08:52

score 0 · Answer 2 · answered Nov 03 '11 at 08:51

0

long File.length(). A File object usually represents a path, rather than an open file.

answered Nov 03 '11 at 08:51

Vlad

18,195
4
41
71

2

There's no 'usually' about it. – user207421 Nov 03 '11 at 10:06

score 0 · Answer 3 · answered Nov 03 '11 at 09:19

Without constructing any object for a particular file,How can you use the properties of file class. OPEN a file means that you are decoding the file data in your compatible format(.txt/.bmp/.pdf etc). SO you have to first

File file=new File("File Name");

File Name-->file name of file to which you want to deal. Then use file.length();

In this phenomenon you are not opening any file,you are just passing reference(address) of the file and retrieving its size. thats it. i hope this will beneficial to you.

File size without opening the file

3 Answers3