public static void mainString args String cardID = 0056432345; Long longCardId = LongparseLongcardID; 10进制转hex 16进制 String cardIdHexString = LongtoHexStringlongCardId;

public static void main(String[] args) { String cardID = "0056432345"; Long longCardId = Long.parseLong(cardID); //10进制转hex 16进制 String cardIdHexString = Long.toHexString(longCardId); //035D16D9 String cardIdHexStringUpper = cardIdHexString.toUpperCase(); //035D16D9 String cardIdHexStringPadded = String.format("%08s", cardIdHexStringUpper).replace(' ', '0'); //035D16D9 System.out.println(cardIdHexStringPadded); }