private void readImage(String filename)  throws FileNotFoundException, IOException {         FileInputStream fIn = new FileInputStream(filename); //需要替换这边的两句：         JPEGImageDecoder jpeg_decode = JPEGCodec.createJPEGDecoder(fIn);         BufferedImage image = jpeg_decode.decodeAsBufferedImage();         width = image.getWidth();         height = image.getHeight();         int[] rgbdata = new int[width * height];         image.getRGB(0,0,width,height,rgbdata,0,width);         bytes = new byte[rgbdata.length];         doubles = new double[rgbdata.length];         for (int i = 0; i < bytes.length; i++) {           bytes[i]    = (byte)  (rgbdata[i] & 0xFF);           doubles[i]  = (double)(rgbdata[i]);         }     }