图片加密

    public static void main(String[] args) {
        try {
//            setImgByte();
            resetImg();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
    }
    public static void setImgByte() throws FileNotFoundException {
        File file = new File("d:\\user\\01411436\\桌面\\tool\\cabinet_green.png");
        FileInputStream inputStream = new FileInputStream(file);

        String flag = "我是一张图片";
        FileOutputStream outputStream = new FileOutputStream(new File("d:\\user\\01411436\\桌面\\tool\\cabinet_green2.png"));
        try {
            byte[] cs = flag.getBytes("utf-8");
            byte[] bytes = IOUtils.toByteArray(inputStream);
            byte[] tbytes = new byte[bytes.length + cs.length];
            System.arraycopy(cs, 0, tbytes, 0, cs.length);
            System.arraycopy(bytes, 0, tbytes, cs.length, bytes.length);

            IOUtils.write(tbytes, outputStream);

        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public static void resetImg() throws FileNotFoundException {
        File file = new File("d:\\user\\01411436\\桌面\\tool\\cabinet_green2.png");
        FileInputStream inputStream = new FileInputStream(file);

        try {
            byte[] bytes = IOUtils.toByteArray(inputStream);
            byte[] flag = new byte[18];
            System.arraycopy(bytes, 0, flag, 0, 18);
            String s = new String(flag, "UTF-8");
            if (s.equals("我是一张图片")) {
                FileOutputStream outputStream = new FileOutputStream(new File("d:\\user\\01411436\\桌面\\tool\\cabinet_green3.png"));

                byte[] tbytes = new byte[bytes.length - flag.length];
                System.arraycopy(bytes, 18, tbytes, 0, tbytes.length);
                IOUtils.write(tbytes, outputStream);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }