JS regex to Java, syntax issues

Question

I have this to big regex that I use in JavaScript to validate email address.

/^(([^<>()[\]\\.,;:\s@\"]+(\.[^<>()[\]\\.,;:\s@\"]+)*)|(\".+\"))@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\])|(([a-zA-Z\-0-9]+\.)+[a-zA-Z]{2,}))$/

When I try to used them in Java, I get syntax errors.

Unclosed character class near index 154 /^(([^<>()[]\.,;:\s@\"]+(.[^<>()[]\.,;:\s@\"]+)*)|(\".+\"))@(([[0-9]{1,3}.[0-9]{1,3}.[0-9]{1,3}.[0-9]{1,3}])|(([a-zA-Z-0-9]+.)+[a-zA-Z]{2,}))$/ ^

I'm using http://www.regexplanet.com/ to test the regex.

Is there any way to convert or escape chars or something like this? Thanks!

you do know it's very hard to get a regex to validate an email (as per RFC 822), right? http://www.ex-parrot.com/pdw/Mail-RFC822-Address.html. See discussion here: http://stackoverflow.com/questions/201323/using-a-regular-expression-to-validate-an-email-address — Lucas Pottersky, Nov 26 '15 at 18:15
@DaveNewton If not valid client side , do not send to server ? — guest271314, Nov 26 '15 at 18:28
@guest271314 If a web form was the only way someone could send data to the server, sure. But it isn't, and believing it is leaves you *wide* open to the most *trivial* of hacks. — Dave Newton, Nov 26 '15 at 18:37
@guest271314 Use both client-side validation (for immediate, high-level feedback) *and* server-side validation to protect your data. — Dave Newton, Nov 26 '15 at 18:56

score 1 · Answer 1 · edited May 23 '17 at 10:27

I scaped some characters, the result is this:

/^
    (
        (
            [^<>()\[\]\\.,;:\s@\"]+
            (\.[^<>()\[\]\\.,;:\s@\"]+)*
        )
        |
        (
            \".+\"
        )
    )

    @

    (
        (\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\])
        |
        (([a-zA-Z\-0-9]+\.)+[a-zA-Z]{2,})
    )

$/

regexplanet.com:link

Seems like the problem was that there are some [ unescaped.

Anyway I encorage you to see this question: What-is-the-best-java-email-address-validation-method

score 1 · Accepted Answer · answered Nov 26 '15 at 19:28

This is the JS regex as a Java string literal:

"(([^<>()\\[\\].,;:\\s@\"]+(\\.[^<>()\\[\\].,;:\\s@\"]+)*)|(\".+\"))@((\\[[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}\\])|(([a-zA-Z0-9-]+\\.)+[a-zA-Z]{2,}))"

The anchors (^$) have been removed, since they're not needed when calling matches().

All \, except \", have been doubled.

[ inside a class ([]) needed escaping, so escape added (\\[).

. inside a class ([]) don't need escaping, so escape removed.

- inside a class ([]) don't need escaping if placed last, so moved to end.

score 0 · Answer 3 · answered Dec 02 '15 at 13:25

0

I share with all the final regex Java email address regex validator

answered Dec 02 '15 at 13:25

mauriblint

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JS regex to Java, syntax issues

3 Answers3