java 读取图片文件再生成新图片

public static void createIcon(byte[] imageData, String iconFileName, int width, int height) throws IOException {
        double Ratio = 0.0;
        BufferedImage bi = ImageIO.read(new ByteArrayInputStream(imageData));
        if ((bi.getHeight() > width) || (bi.getWidth() > height)) {
            if (bi.getHeight() > bi.getWidth())
                Ratio = (double)width / bi.getHeight();
            else
                Ratio = (double)height / bi.getWidth();
        }
        AffineTransformOp op = new AffineTransformOp(AffineTransform.getScaleInstance(Ratio, Ratio), null);
        Image iconImage = op.filter(bi, null);

        File file = new File(iconFileName);
        if (!file.exists()) {
            File folder = file.getParentFile();
            if (folder != null && !folder.exists()) {
                FileUtils.forceMkdir(folder);
            }
            file.createNewFile();
        }

        ImageIO.write((BufferedImage) iconImage, "jpg", file);
    }

    public static void main(string[] args) throws IOException{
        File file = new File("c://1.jpg");
        InputStream inputStream = new FileInputStream(file);
        byte[] bytes = new byte[(int)(file.length())];
        int set = 0;
//        while (true) {
//            int read = inputStream.read(bytes, set, (int)(file.length()));
//            if (read == -1)
//                break;
//            set += read;
//        }                 //这种方式有时候行有时候不行，还没找到缘由
        while (set < (int)(file.length())) {
            int read = inputStream.read(bytes, set, (int)(file.length()) - set);
            if (read == -1)
                break;
            set += read;
        }

        createIcon(bytes, "c://2.jpg", 300, 300);
    }