How to get content type of a file which has no extension?

Question

I have saved all types of file without extension. When reading through Java code, how to get content type of file?

File file = "/admin/sun"
byte[] pdfByteArray = FileUtils.readFileToByteArray(file);
if (fileName.endsWith(".pdf")) {
    response.setContentType("application/pdf");
} else {
    response.setContentType("image/jpeg");
}
response.getOutputStream().write(pdfByteArray);
response.getOutputStream().flush();

What is if the file extension .pdf or .jpeg it is working then without extension how to get content-type?

score 2 · Accepted Answer · answered Jan 18 '14 at 09:16

2

Use Files.probeContentType(path) in jdk7. Or detect the file type yourself, according to different file type specifications. Say pdf http://www.adobe.com/devnet/pdf/pdf_reference.html

answered Jan 18 '14 at 09:16

Weibo Li

3,565
3
24
36

I test that with some csv files (with extension), and method returns text/csv, but if I delete the extension from file's name, it doesn't work. It returns text/plain – Angie Quijano Jun 12 '19 at 16:05

score 1 · Answer 2 · edited May 23 '17 at 12:02

1

You better do not rely on extensions. Find the mime type of the file.

See this SO question: Getting A File's Mime Type In Java

You must read the mime type with Files.probeContentType(path).

More relevant information on mime types

edited May 23 '17 at 12:02

Community

1
1

answered Jan 18 '14 at 09:12

ssedano

8,322
9
60
98

This should have just been a close vote. – Jon Skeet Jan 18 '14 at 09:14
I wanted to make clear that he must rely on mime type and how to get to it. But I already vote for close – ssedano Jan 18 '14 at 09:18
1

That would have been better as a comment then. One close vote, one comment - not just an "answer" which in itself doesn't really answer the question (until an edit), but just redirects... – Jon Skeet Jan 18 '14 at 09:28
yeah. i upvoted – Maheshbabu Jammula Apr 06 '17 at 15:03

How to get content type of a file which has no extension?

2 Answers2