Java - Regular Expression

Question

I have a regular expression to validate email:

Validemail = ^[^\\^~`'!@$#=%&*()+|{}:;,><?\"\\/\\[\\]\\\\\\s-\\.]([^\\^~`'!@$#=%&*()+|{}:;,><?\"\\/\\[\\]\\\\\\s\\.]|\\.(?!\\.+?))*[^\\^~`'!@$#=%&*()+|{}:;,><?\"\\/\\[\\]\\\\\\s-\\.]@[^\\^~`'!@$#=%&*()+|{}:;,><?\"\\/\\[\\]\\\\\\s\\.]*[^\\^~`'!@$#=%&*()+|{}:;,><?\"\\/\\[\\]\\\\\\s-\\.]\\.(?!\\.+?)[^\\^~`'!@$#=%&*()+|{}:;,><?\"\\/\\[\\]\\\\0-9\\s-\\_]{2,40}$$

This validation is accepting EG: kate@stack---overlow.com

However I want to restrict the domain name after @ and before . so have only 1 hyphen.

Update:

I would not prefer making that check using contains rather make it a part of regex.

Why is there a `$$` at the end? Perhaps your additional check would be simpler to implement as a separate check. e.g. `text.contains("--")` — Peter Lawrey, May 11 '11 at 08:28
@Joachim because domains with more than one hyphen isn't cool. — Gio Borje, May 11 '11 at 08:28
Also: preventing `--` would exclude all email adresses with [IDN domains](http://en.wikipedia.org/wiki/Internationalized_domain_name). — Joachim Sauer, May 11 '11 at 08:29

score 3 · Answer 1 · edited May 23 '17 at 12:19

3

I'd recommend first validating the email address with the JavaMail API, as described in this answer: validate e-mail field using regex. That way you don't have to deal with a complicated regex to handle all of the details of the RFC 822 specification on email addresses.

Once it passes that, then add your additional check for a single hyphen after @ and before ., e.g.:

public boolean isValidEmail(String email) {
    try {
        String address = new InternetAddress(email).getAddress();
        return address.matches(".*@[^-]*-{0,1}[^-]*\\..*");
    } catch (AddressException e) {
        // you should probably log here for debugging
        return false;
    }
}

edited May 23 '17 at 12:19

Community

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answered May 11 '11 at 08:33

WhiteFang34

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Yeah what iam saying is subsequnet hyphens we shld discourage. – jaisri_88 May 11 '11 at 08:49
If you just want to prevent sequences of hyphens then you could change the check here to `return !address.contains("--");` much like Peter suggested. The point is here though is to use the JavaMail API to do the hard work of validating an email address. Then you can easily perform your additional restriction(s) afterwards. – WhiteFang34 May 11 '11 at 08:55

AabinGunz · Answer 2 · 2011-05-11T08:56:19.217

0

try this, this regex will only accept 1 -

((\w|-)+(\.\w+)?)+@[\w]+\-{0,1}[\w]+\.\w+

edited May 11 '11 at 08:56

answered May 11 '11 at 08:41

AabinGunz

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Java - Regular Expression

Update:

2 Answers2