Custom RegEx for Username/Email Address Java

Question

Somehow I find it really hard to create a RegEx on my own and I am sure one of you does know how to work with them. My question: I want users, who register, to only be able to enter an email address of this format: ?.????@example.com.

To clear up, my RegEx should look for if there is only one character in the first position, followed by a dot, an infinite number of characters, an at-symbol, followed by "example.com".

Is it even possible to allow RegEx to look for full strings (example.com in this case) and if so, what would that RegEx look like? (I'd like an full example).

EDIT: By characters I mean alphanumeric characters (^[a-zA-z]$)

Thanks in advance!

Parsing emails with regex isn't simple at all, I would recommend to read [this](http://www.regular-expressions.info/email.html) article, it explains the trade-offs in using one regex over another and what are some standards to use (even with standards, there are still some trade-offs). — alturkovic, Jan 28 '17 at 13:05

Ashraful Islam · Accepted Answer · 2017-01-28T13:00:55.190

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Here is the regex :

^[a-zA-Z0-9]\.[a-zA-Z0-9]+@example\.com$

Demo and Explanation : https://regex101.com/r/BPFHvl/4

edited Jan 28 '17 at 13:00

answered Jan 28 '17 at 12:36

Ashraful Islam

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This would validate: _._@example.com – alturkovic Jan 28 '17 at 12:40
Amerongen says character, not that only alphanumeric – Ashraful Islam Jan 28 '17 at 12:44
If possible, I did indeed meant alphanumeric characters, I will edit my question. Also, as shown in your example, `atest.sss@example.com` would validate as well. – J van Amerongen Jan 28 '17 at 12:49
@JvanAmerongen Answer updated – Ashraful Islam Jan 28 '17 at 12:52
I tried this RegEx, but it doesn't seem to work. Here's a fixed one: `^[a-zA-Z0-9]\.[a-zA-Z0-9]+@example\.com$`. – J van Amerongen Jan 28 '17 at 12:59
I forget to remove \ – Ashraful Islam Jan 28 '17 at 13:01

Custom RegEx for Username/Email Address Java

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