ip，email，銀行卡號匹配

import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * Created by admin on 2015/8/8.
 */
public class RegularUtil {
    public static boolean isIP(String ip) {
        Pattern pattern = Pattern.compile("\\b((?!\\d\\d\\d)\\d+|1\\d\\d|2[0-4]\\d|25[0-5])\\.((?!\\d\\d\\d)\\d+|1\\d\\d|2[0-4]\\d|25[0-5])\\.((?!\\d\\d\\d)\\d+|1\\d\\d|2[0-4]\\d|25[0-5])\\.((?!\\d\\d\\d)\\d+|1\\d\\d|2[0-4]\\d|25[0-5])\\b");
        Matcher matcher = pattern.matcher(ip);
        return matcher.matches();
    }

    public static boolean isEmail(String email) {
        //Pattern pattern = Pattern.compile("^([a-zA-Z0-9_\\-\\.]+)@((\\[[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}\\.)|(([a-zA-Z0-9\\-]+\\.)+))([a-zA-Z]{2,4}|[0-9]{1,3})(\\]?)$");
        Pattern pattern = Pattern.compile("^([a-zA-Z0-9_\\-\\.]+)@((\\[[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}\\.)|(([a-zA-Z0-9\\-]+\\.)+))([a-zA-Z]{2,4}|[0-9]{1,3})(\\]?)$");
        Matcher matcher = pattern.matcher(email);
        return matcher.matches();
    }

    public static boolean isBankCard(String cardId){
        char bit = getBankCardCheckCode(cardId.substring(0, cardId.length() - 1));
        return cardId.charAt(cardId.length() - 1) == bit;
    }

    /**
     * 從不含校驗位的銀行卡卡號採用 Luhm 校驗算法獲得校驗位
     * @param nonCheckCodeCardId
     * @return
     */
    private static char getBankCardCheckCode(String nonCheckCodeCardId) {
        if(nonCheckCodeCardId == null || nonCheckCodeCardId.trim().length() == 0
                || !nonCheckCodeCardId.matches("^[0-9]*$")) {//或者"\\d+"
            throw new IllegalArgumentException("Bank card code must be number!");
        }
        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');
    }
}