The method doesn't work correctly when using matches (), regex, trying to validate Phone number

Question

Good afternoon, I need to write a method that will validate the phone number . I need the number can only contain numbers (0-9) and these characters : "()" "-" "+" , but everything else is forbidden!

For example :

 +210-998-234-01234 -OK
  210-998-234-01234-OK
 +21099823401234-OK
 +210-998-234-01234 -OK
 +210-(998)-(234)-(01234) - OK

+210-99A-234-01234 - FALSE , +210-999-234-0""234 -FALSE , +210-999-234-02;4 - FALSE

If the number contains something unresolved it should throw exception. I wrote this method but for some reason it doesn't work right. Please explain where I made a mistake when using matches()

I will be grateful for your help!

public void validatePhoneNumber(String phoneNumber) {
        if (!phoneNumber.matches("[ˆ0-9()\\-+]")) {
            throw new IncorrectlyEnteredDataException("Phone number have unresolved characters");

        }

Is this a valid phone number? `-210+998-234-01234` What about this? `+210-998)-(234-(01234` — Abra, Sep 06 '20 at 18:11
@Abra well, you are right, can you tell me how to write this method correctly? — Amir Kerimov, Sep 06 '20 at 19:16

DigitShifter · Accepted Answer · 2020-09-07T05:49:40.283

This regex will work for your phone numbers:

"^\\+?\\d{3}(?:\\d{11}|(?:-\\d{3,}){3}|(?:-\\(\\d{3,}\\)){3})"

But if you want to match all kind of variations of phone numbers, then see this solution - where Java generates REGEX for valid phone numbers:

How to validate phone numbers using regex

Regex shown in test bench and context:

public class TestBench {

        private final static Pattern VALID_PHONE_NUMBER_PATTERN =
                Pattern.compile("^\\+?\\d{3}(?:\\d{11}|(?:-\\d{3,}){3}|(?:-\\(\\d{3,}\\)){3})");

        public static void main (String[] args) {
            List<String> inputNumbers = Arrays.asList(
                    "+210-998-234-01234",       // PASS
                    "210-998-234-01234",        // PASS
                    "+21099823401234",          // PASS
                    "+210-(998)-(234)-(01234)", // PASS
                    "+210-99A-234-01234",       // FAIL
                    "+210-999-234-0\"\"234",    // FAIL
                    "+210-999-234-02;4",        // FAIL
                    "-210+998-234-01234",       // FAIL
                    "+210-998)-(234-(01234"     // FAIL
            );

            for (String number : inputNumbers) {
                validatePhoneNumber(number);
            }
        }

    private static void validatePhoneNumber(String phoneNumber) {
        Matcher matcher = VALID_PHONE_NUMBER_PATTERN.matcher(phoneNumber);
        if(matcher.matches()) {
            System.out.println("This is a valid phone number: " + matcher.group());
        }
    }

}

Output:

This is a valid phone number: +210-998-234-01234
This is a valid phone number: 210-998-234-01234
This is a valid phone number: +21099823401234
This is a valid phone number: +210-(998)-(234)-(01234)

Comment:

Notice: You can change on how many numbers you can tolerate by changing X and Y in the regex and so on, see below for clarification:

"^\\+?\\d{3}(?:\\d{X}|(?:-\\d{Y,}){3}|(?:-\\(\\d{Y,}\\)){3})"

In the regex suggested, we asume that there will always be three digits first before another variation comes.

The method doesn't work correctly when using matches (), regex, trying to validate Phone number

1 Answers1