i am validating email on server side

[Karamjeet singh]

i am validating email on server side
i have code of javascript whch validates
but i want pure java to validate
i ask from my faculty
she says you can do this by patterns
but i don't know where to start

[Vikas Nahar]

What kind of validation are aiming at? Just the syntax validation?

Syntax validation can be done using parsers.
For a more detailed validation we are having a discussion on the following thread maybe it might help you.

https://coderanch.com/t/453931/Other-JSE-JEE-APIs/java/handle-wrong-mail-address-while

[Charles 'King]

karamjeet singh wrote:i am validating email on server side
i have code of javascript whch validates
but i want pure java to validate
i ask from my faculty
she says you can do this by patterns
but i don't know where to start

You're going to have to exert a little more effort if you want help. Post some code and ideas. Give us an idea of your skill level (Beginner, Intermediate, etc...). This isn't a code factory

[Karamjeet singh]

....................public class checkUser extends HttpServlet {
    
    public static boolean isValidEmailAddress(String email)
    { 
        String regex = "^[_A-Za-z0-9-]+(\\.[_A-Za-z0-9-]+)*@[A-Za-z0-9-]+(\\.[A-Za-z0-9-]+)*(\\.[_A-Za-z0-9-]+)" ;
        return email.matches(regex) ;
    }
    protected void processRequest(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        response.setContentType("text/html;charset=UTF-8");
        PrintWriter out = response.getWriter();
        
        try
        {
           .....................
            

i am putting this code outside processRequest method
if i put this inside it give me error
how can i do it

[Paul Clapham]

But that's just a basic question about Java programming, isn't it? You can't put a method inside another method regardless of whether it's validating an e-mail address or anything else.

[Karamjeet singh]

i know that
but i want the value of that method to validate
how can i do it

[Karamjeet singh]

see i am receiving value from user
on the base of that value i am validating
from which method i can do this
any any hints

[Mark E Hansen]

karamjeet singh wrote:see i am receiving value from user
on the base of that value i am validating
from which method i can do this
any any hints

Just call the validation method from within your processRequest method.

What's the problem? If you get an error, show the code that is causing the error and show us the error you're getting.

[David Newton]

FWIW, the "real" regex for validating an email address is about a page long. It's actually somewhat entertaining.

[Garrett Rowe]

FWIW, the "real" regex for validating an email address is about a page long. It's actually somewhat entertaining.

That made me curious so I found this: http://www.ex-parrot.com/~pdw/Mail-RFC822-Address.html ... gnarly!

[Paul Clapham]

David Newton wrote:FWIW, the "real" regex for validating an email address is about a page long. It's actually somewhat entertaining.

What is less entertaining is when somebody decides they have to validate e-mail addresses, so they implement a regex which determines your actual e-mail address is not valid.

[Rob Spoor]

I just use javax.mail.internet.InternetAddress to handle the validation for me.

[Jelle Klap]

David Newton wrote:FWIW, the "real" regex for validating an email address is about a page long. It's actually somewhat entertaining.

I don't think it's even technically possible to write a regular expression that fully complies with the formal specification of a valid e-mail address. Syntax validation of an e-mail address doesn't really buy you a whole lot anyway. If you want to know that a user supplied e-mail address is valid and in use, just send a verification e-mail to the address containg a deeplink with an activation UID. It's a little more hassle for the user, but a far more useful means of validation.

[David Newton]

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Although this regex assumes comments have been stripped.

http://www.ex-parrot.com/~pdw/Mail-RFC822-Address.html

This has been on the internet for a long time, and is reasonably complete.

[Campbell Ritchie]

And anything with a regex that long is not a "beginning" topic.Moving thread.

[Rob Spoor]

Campbell Ritchie wrote:And anything with a regex that long is not a "beginning" topic.Moving thread.

Fixed

[Campbell Ritchie]

I take your point, Rob.