//读取文件到byte[]
    private static byte[] getFileBytes(String file) {
        try {
            File f = new File(file);
            int length = (int) f.length();
            byte[] data = new byte[length];
            new FileInputStream(f).read(data);
            return data;
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }