md5，获取字符串MD5

    public static String getMd5(String text) {
        try{
            MessageDigest md5 = MessageDigest.getInstance("MD5");
            byte[] bytes = md5.digest(text.getBytes(StandardCharsets.UTF_8));

            StringBuilder builder = new StringBuilder();

            for (byte aByte : bytes) {
                builder.append(Integer.toHexString((0x000000FF & aByte) | 0xFFFFFF00).substring(6));
            }
            return builder.toString();
        }catch (Exception e){
            return "";
        }

    }