Java email address validation using regular expression

Question

I am trying to set a regular experssion validation of email address input.

I have this java class which does the validation:

public class EmailValidator implements Validator {

@Override
public void validate(FacesContext facesContext, 
UIComponent uIComponent, Object value) throws ValidatorException {

//Get the component's contents and cast it to a String
String enteredEmail = (String)value;

//Set the email pattern string
Pattern p = Pattern.compile(".+@.+\\.[a-z]+");

//Match the given string with the pattern
Matcher m = p.matcher(enteredEmail);

//Check whether match is found
boolean matchFound = m.matches();

if (!matchFound) {
    FacesMessage message = new FacesMessage();
    message.setDetail("Email not valid - The email must be in the format [email protected]");
    message.setSummary("Email not valid - The email must be in the format [email protected]");
    message.setSeverity(FacesMessage.SEVERITY_ERROR);
    throw new ValidatorException(message);
}
}
}

There is a default pattern in this code. However, I am trying to replace it with another pattern instead.

Pattern:

/^(?:(?:(?:[^@,"[]\x5c\x00-\x20\x7f-\xff.]|\x5c(?=[@,"[]\x5c\x00-\x20\x7f-\xff]))(?:[^@,"[]\x5c\x00-\x20\x7f-\xff.]|(?<=\x5c)[@,"[]\x5c\x00-\x20\x7f-\xff]|\x5c(?=[@,"[]\x5c\x00-\x20\x7f-\xff])|.(?=[^.])){1,62}(?:[^@,"[]\x5c\x00-\x20\x7f-\xff.]|(?<=\x5c)[@,"[]\x5c\x00-\x20\x7f-\xff])|[^@,"[]\x5c\x00-\x20\x7f-\xff.]{1,2})|"(?:[^"]|(?<=\x5c)"){1,62}")@(?:(?!.{64})(?:[a-zA-Z0-9][a-zA-Z0-9-]{1,61}[a-zA-Z0-9].?|[a-zA-Z0-9].?)+.(?:xn--[a-zA-Z0-9]+|[a-zA-Z]{2,6})|[(?:[0-1]?\d?\d|2[0-4]\d|25[0-5])(?:.(?:[0-1]?\d?\d|2[0-4]\d|25[0-5])){3}])$/

May I know can this pattern be used? Or do I need to put some brackets etc to make it work? I am receiving illegal start of expression errors now.

What are you using the pattern for?

8vius
– 8vius

2011-08-17 04:58:30 +00:00
Commented Aug 17, 2011 at 4:58 — 8vius
– 8vius, Commented Aug 17, 2011 at 4:58

Radu Ciopraga · Accepted Answer · 2011-08-17 06:38:24Z

5

You could also use the EmailValidator from Apache Commons Validator.

answered Aug 17, 2011 at 6:38

Radu Ciopraga

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Comments

Jeffrey · Accepted Answer · 2011-08-17 04:58:59Z

0

I'm sure that regex can be used, but you'll have to properly insert it into your code. However, the best way to check if an email is valid is to send it an email. Here's a good site for email verification with regex, and of course you can always search this site for the many similar questions.

answered Aug 17, 2011 at 4:58

Jeffrey

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fgysin · Accepted Answer · 2011-08-17 06:10:29Z

0

You can use that RegEx (or any you want, at that) but keep in mind to excape the backslash \ in java strings (by entering two \\).

Here is a page that lets you transform regex strings into Java strings, i.e. it does all the escaping of weird characters for you.... (Page seems to be down right now, but it was working yesterday, so just check in later...)

answered Aug 17, 2011 at 6:10

fgysin

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8vius · Accepted Answer · 2011-08-17 14:12:30Z

0

If you are trying to do an email validation this pattern works and is much shorter ^[a-z0-9!#$%&'*+/=?^_{|}~-]+(?:\.[a-z0-9!#$%&'*+/=?^_{|}~-]+)*@(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\\.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])?$

I use java's regex util package (java.util.regex.*) here's the documentation on it and on regular expressions in java in general:

http://java.sun.com/developer/technicalArticles/releases/1.4regex/

edited Aug 17, 2011 at 14:12

answered Aug 17, 2011 at 5:00

8vius

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2 Comments

RUiHAO Over a year ago

so all i have to do is escape all / and \ ?If I escape only "/" it does not work

8vius Over a year ago

I modified the regex to work for java, just follow the documentation I gave you and you should be able to do it without a problem.

Jack · Accepted Answer · 2013-04-10 19:38:41Z

0

Try this please, works very fine with me.

String expressionForEmail = "^[\\w\\.-]+@([\\w\\-]+\\.)+[a-zA-Z]{2,4}$";

answered Apr 10, 2013 at 19:38

Jack

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Comments

Imran Ali · Accepted Answer · 2011-08-17 11:16:44Z

-2

you can use this expression for email validation "[A-Za-z]+@+[A-Za-z]+\.+[A-Za-z]{2,4}+$" it is much more simpler to do that.

edited Aug 17, 2011 at 11:16

answered Aug 17, 2011 at 11:07

Imran Ali

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1 Comment

CanSpice Over a year ago

That regex will not validate all valid email addresses.

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