如何将WritableRaster转换为字节数组？

Question

我想将WritableRaster转换为字节数组，但无法转换为DataBufferByte

        BufferedImage thumbnail = new BufferedImage(100, 100, BufferedImage.TYPE_INT_RGB);
        thumbnail.createGraphics().drawImage(ImageIO.read(imageFile).getScaledInstance(100, 100, Image.SCALE_SMOOTH),0,0,null);


        WritableRaster raster = thumbnail.getRaster();

        // throws ClassCastException
        // java.awt.image.DataBufferInt cannot be cast to java.awt.image.DataBufferByte
        DataBufferByte imgData = (DataBufferByte) raster.getDataBuffer();

        byte[] data = imgData.getData();