자바 에서 그림 파일 형식 가 져 오기

public static void main(String[] args) {

        File f = new File("c://test.jpg");

        if (f.exists()) {

            System.out.println(getFormatInFile(f));

        }

    }



    // Returns the format of the image in the file 'f'.

    // Returns null if the format is not known.

    public static String getFormatInFile(File f) {

        return getFormatName(f);

    }

    

    // Returns the format name of the image in the object 'o'.

    // Returns null if the format is not known.

    private static String getFormatName(Object o) {

        try {

            // Create an image input stream on the image

            ImageInputStream iis = ImageIO.createImageInputStream(o);

    

            // Find all image readers that recognize the image format

            Iterator<ImageReader> iter = ImageIO.getImageReaders(iis);

            if (!iter.hasNext()) {

                // No readers found

                return null;

            }

    

            // Use the first reader

            ImageReader reader = iter.next();

    

            // Close stream

            iis.close();

    

            // Return the format name

            return reader.getFormatName();

        } catch (IOException e) {

            //

        }

        

        // The image could not be read

        return null;

    }