Ever see "application/octet-stream" or "text/plain" or "text/html"? Those are called MIME types. ("MIME" stands for Multi-purpose Internet Mail Extensions.)
If your Java program has files and needs to figure out their MIME types, this library will help.
import org.overviewproject.mime_types.MimeTypeDetector
// ...
File file = new File("foo.txt");
MimeTypeDetector detector = new MimeTypeDetector();
String mimeType = detector.detectMimeType(file); // "text/plain"
// ... or ...
InputStream stream = new ByteArrayInputStream("words".getBytes("utf-8"))
String mimeType = detector.detectMimeType("filename", stream); // "text/plain"No library can figure out MIME types perfectly. But there's a standard, called shared-mime-info. This library follows its algorithm to the letter.
You need two things to detect a file's type:
- The file's name
- The first few bytes of the file's content
The bytes aren't always needed; for speed, you can pass a callback instead of the actual bytes, and this library will only invoke the callback when it's absolutely necessary. There's an async version, too.
For a method that matches the files you have, read the MimeTypeDetector docs.
Big thanks to Medsea Business Solutions S.L. for most of this code. I merely adjusted the API. (The original project at http://sourceforge.net/p/mime-util/ seems to be dead.)