how to know actual file type in java

Question

I have file for example 5555.33 but in fact file is arj archive file

String ext = FilenameUtils.getExtension("C:\\5555.33");

the Extension returns 33 file. How to get actual file type arj from this file

The extension isn't `arj` it's `33`. If the extension were `arj`, the file would be named `5555.arj`. — Kayaman, Apr 29 '15 at 10:57
The extension is no longer `arj`. You can try getting the mime-type: http://stackoverflow.com/questions/51438/getting-a-files-mime-type-in-java — ceekay, Apr 29 '15 at 11:00

score 1 · Accepted Answer · answered Apr 29 '15 at 13:33

1

ARJ archive files start with 0x60, 0xEA bytes. Just read the first two bytes to determine whether file is ARJ archive or not.

answered Apr 29 '15 at 13:33

AzKa

score 0 · Answer 2 · edited Apr 29 '15 at 11:42

0

It seems like you want the content after '.' . For this you can try

String str = "abc.txt";
System.out.println(str.substring(str.lastIndexOf(".")+1));

You can use

Files.probeContentType(path)

to know what type of file it is refered to

edited Apr 29 '15 at 11:42

ceekay

answered Apr 29 '15 at 11:03

Ashishkumar Singh

It's already stated, that he does NOT want the actual extension (the thingy that's now behind the "."), but the ?old? or maybe just the mime-type (which is already answered in another question) – ceekay Apr 29 '15 at 11:05

2 Answers2