How to get an image type without knowing its file extension?

Question

I need to know a file extension without having the file extension? Is this possible with the java IO API?

I'm getting the following exception while reading a JPG file:

javax.imageio.IIOException: Unsupported Image Type

Does anyone have any ideas how to solve this?

When i try to open the image in a normal image viewer in Mac OS X or Windows, it works just fine.

Is there any chances the file was renamed to a different type and it's original type is different from the extension?

http://stackoverflow.com/questions/51438/getting-a-files-mime-type-in-java ? — mindas, Sep 21 '12 at 13:46

score 4 · Accepted Answer · answered Sep 21 '12 at 13:47

You can get the mime type with this code.

String imageName = "C:\\Documents and Settings\\home\\Desktop\\P092870.jpg";
File input = new File(imageName);
System.out.println("System Type description of " + input.getName() + " is " + 
          FileSystemView.getFileSystemView().getSystemTypeDescription(input));
System.out.println("Mime Type of " + input.getName() + " is " +
          new MimetypesFileTypeMap().getContentType(input));

score 0 · Answer 2 · edited Sep 21 '12 at 17:45

You can use mime-util library. My sample code will get the mime type of the file.

    String imagePath = "filepath";
    File file = new File(imagePath);

    if (MimeUtil.getMimeDetector(MagicMimeMimeDetector.class.getName()) == null)  {
        MimeUtil.registerMimeDetector(MagicMimeMimeDetector.class.getName());
    }
    Collection<MimeType> mimeTypes = MimeUtil.getMimeTypes(file);
    for (MimeType mimeType : mimeTypes) {
        System.out.println(mimeType.getMediaType());
    }

How to get an image type without knowing its file extension?

2 Answers2

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