How to get byte[] from the Image?

[Anonymous]

Can anyone give me a hint on how to a get a byte[] array or InputStream from the Image/Icon object. Need to store an image that doesn't come from the filesytem in the DB's LONG RAW field. I can get int[] with PixelGrabber class, but how does one convert it to byte[]? thanks...

[Thomas Suer]

Please try this:

    public static byte [] getByteArrayOfIcon(final Class baseClass, final String gifFile)
    {
        final byte[][] buffer = new byte[1][];
        try
        {
            InputStream resource = baseClass.getResourceAsStream(gifFile);
            if (resource == null)
            {
                return null;
            }
            BufferedInputStream   in  = new BufferedInputStream(resource);
            ByteArrayOutputStream out = new ByteArrayOutputStream(1024);
            buffer[0] = new byte[1024];
            int n;
            while ((n = in.read(buffer[0])) > 0)
            {
                out.write(buffer[0], 0, n);
            }
            in.close();
            out.flush();
            buffer[0] = out.toByteArray();
        }
        catch (IOException ioe)
        {
            ioe.printStackTrace();
            return null;
        }
        return buffer[0];
    }

Good luck
Tom

[Eric Hoskland]

I am having a similar problem:
I want to convert an java.awt.image into a byte array NOT into an int array. Shouldn't there be a way to specify a custom colorspace and colormodel to pixelgrabber so that it grabs the pixels and puts them into a byte array opposed to a int array??? Or is this just not possible
The image ONLY exists as a java.awt.image NEVER as anything else so there isn't a prior step that I can intercept (which is how the example above does it)
Thanks

[Martin Thorpe]

ok this is the sort of problem I am having too. I understand all of the above method apart from the baseClass stuff!?!?! can anyone explain that to me? How I should call this method?

thanks for taking the time to read.

cheers
Martin

[Craig Wood]

The Class argument is the class whose class loader will be asked to locate the file (see getResource Method Detail in Class api). If it is simply the enclosing class you can use the keyword this. If called from a static context you will need to use the MyClass.class form of class reference. If called from within an inner class you can use a member variable reference created at construction.

class MyClass {
    MyClass myClass;
 
    public MyClass() {
        myClass = this;
        getBytes(this, ...
        ...
    }
 
    myButton.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent e) {
            getBytes(myClass, ...
 
    public static void main(String[] args) {
        getBytes(MyClass.class, ...

See the tutorial page How to Use Icons, especialy the section Loading Images Using getResource.

[Ben Hur]

Why not just write the image out using the javax.imageio.ImageIO which has the following static method:

public static boolean write(RenderedImage im,
                                String formatName,
                                OutputStream output) throws IOException;

You're image does get encoded into the format you specify (i.e. jpeg or png for example), which does seem to be a good side-effect.

Take a peek at the
Java Almanac.