计算机那些事Java

Java: Get Credit Card Type By Its Number

It is a simple function that can identify the credit card type by its number. Get help from this page: http://www.regular-expressions.info/creditcard.html

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public class Util {

    public static String getCreditCardTypeByNumber(String creditCardNumber) {

        String regVisa = "^4[0-9]{12}(?:[0-9]{3})?$";
        String regMaster = "^5[1-5][0-9]{14}$";
        String regExpress = "^3[47][0-9]{13}$";
        String regDiners = "^3(?:0[0-5]|[68][0-9])[0-9]{11}$";
        String regDiscover = "^6(?:011|5[0-9]{2})[0-9]{12}$";
        String regJCB= "^(?:2131|1800|35\\d{3})\\d{11}$";


        if(creditCardNumber.matches(regVisa))
            return "visa";
        if (creditCardNumber.matches(regMaster))
            return "mastercard";
        if (creditCardNumber.matches(regExpress))
            return "amex";
        if (creditCardNumber.matches(regDiners))
            return "DINERS";
        if (creditCardNumber.matches(regDiscover))
            return "discover";
        if (creditCardNumber.matches(regJCB))
            return "jcb";
        return "invalid";
    }
}