Here's a "magic" number package which allows content-type (mime-type) determination from files and byte arrays. It makes use of the magic(5) Unix content-type files to implement the same functionality as the Unix file(1) command in Java which detects the contents of a file. It uses either internal config files or can read /etc/magic, /usr/share/file/magic, or other magic(5) files and determine file content from File, InputStream, or byte[].

• For more information, visit the home page.
• The source code be found on the git repository.
• Maven packages are published via

Enjoy, Gray Watson

To get started you use the SimpleMagic package like the following:

// create a magic utility using the internal magic file
ContentInfoUtil util = new ContentInfoUtil();
// if you want to use a different config file(s), you can load them by hand:
// ContentInfoUtil util = new ContentInfoUtil("/etc/magic");
// ...
ContentInfo info = util.findMatch("/tmp/upload.tmp");
// or
ContentInfo info = util.findMatch(inputStream);
// or
ContentInfo info = util.findMatch(contentByteArray);

Once you have the ContentInfo it provides:

• Enumerated type if the type is common
• Approximate content-name
• Full message produced by the magic file
• Mime-type string if one configured by the config file
• Associated file extensions (if any)

For example:

• HTML, mime 'text/html', msg 'HTML document text'
• Java, msg 'Java serialization data, version 5'
• PDF, mime 'application/pdf', msg 'PDF document, version 1.4'
• gzip, mime 'application/x-gzip', msg 'gzip compressed data, was "", from Unix...'
• GIF, mime 'image/gif', msg 'GIF image data, version 89a, 16 x 16'
• PNG, mime 'image/png', msg 'PNG image, 600 x 371, 8-bit/color RGB, non-interlaced'
• ISO, mime 'audio/mp4', msg 'ISO Media, MPEG v4 system, iTunes AAC-LC'
• Microsoft, mime 'application/msword', msg 'Microsoft Word Document'
• RIFF, mime 'audio/x-wav', msg 'RIFF (little-endian) data, WAVE audio, Microsoft...'
• JPEG, mime 'image/jpeg', msg 'JPEG image data, JFIF standard 1.01'

See the ChangeLog.txt file.