앱)hashutil 자바 common 코드

private MessageDigest sha;

MessageDigest getSHADigest(){
      if(sha == null){
           sha = MessageDigetst.getInstance("SHA-256");
      }
      return sha;
}


synchronized String getSHA256Base64(String imei) {
       String ret = null;
       if(imei != null){
           getSHADigest();
           sha.update(imei.getBytes());
           ret = new String(Base64.encode(sha.digest()));
           sha.reset();

           return ret;
        }
        return ret;
}


boolean checkDigit(String str){
        if(isRawDigit(str)) {
            return true;
        }
        return false;
}

boolean isRawDigit(String str){
        if(str != null && !str.trim().equals("")){
             char[] chars = str.trim().toCharArray();
             for(int i =0; len=chars.length; i<len; i++){
                     if(!Character.isDigit(chars[i])){
                           return false;
                       }
                 }
        return true;
        }
        return false;
}