银行卡卡号是否正确判断（实战）

public class CheckIdCard {/** * 校验银行卡卡号 *  * @param cardId * @return */public static boolean checkBankCard(String cardId) {char bit = getBankCardCheckCode(cardId.substring(0, cardId.length() - 1));if (bit == 'N') {return false;}return cardId.charAt(cardId.length() - 1) == bit;}/** * 从不含校验位的银行卡卡号采用 Luhm 校验算法获得校验位 *  * @param nonCheckCodeCardId * @return */public static char getBankCardCheckCode(String nonCheckCodeCardId) {if (nonCheckCodeCardId == null|| nonCheckCodeCardId.trim().length() == 0|| !nonCheckCodeCardId.matches("\\d+")) {// 如果传的不是数据返回Nreturn 'N';}char[] chs = nonCheckCodeCardId.trim().toCharArray();int luhmSum = 0;for (int i = chs.length - 1, j = 0; i >= 0; i--, j++) {int k = chs[i] - '0';if (j % 2 == 0) {k *= 2;k = k / 10 + k % 10;}luhmSum += k;}return (luhmSum % 10 == 0) ? '0' : (char) ((10 - luhmSum % 10) + '0');}}