invalid email address string check (for school)

Question

I'm working on a project in school and I need to verify 5 email address from an arraylist.

I have to verify that all emails have '@' and '.' and don't have a space. Right now I'm just trying to get first part down.

This is what I have so far and when it calls it pulls all 5 email addresses. It seems like the contains would check for the chars and only return false on the emails that don't have it. I'm not looking for word for word answer. Just a bit of direction.

public static void print_invalid_emails()
{
    for (Student s : myRoster )
    {
        if(s.getEmailAddress().contains("@.") == false)
            System.out.println("Invalid Email: " + s.getEmailAddress());

    }

}

It should be pretty obvious that none of your email address looks like *foo@.com* with a `@.` right next to each other so you will have to split your tests for `@`and `.` — Filburt, Mar 21 '17 at 23:57
And don't try to guess what contains does. Read the javadoc, carefully. https://docs.oracle.com/javase/8/docs/api/java/lang/String.html#contains-java.lang.CharSequence- — JB Nizet, Mar 22 '17 at 00:09

score -1 · Answer 1 · edited May 23 '17 at 12:00

-1

contains check for a String, here your code will return true only if the email adress contains "@." as a String. Try using indexOf :

String email = s.getEmailAddress();

int atIndex = email.indexOf('@');

if (atIndex < 0 || email.indexOf('.', atIndex) < 0 || email.indexOf(' ') >= 0)
    System.out.println("Invalid Email: " + email);

I assumed that the . must be found in the "right part" of the adress, after the @. Otherwise, you don't need atIndex and you can use email.indexOf('.') instead.

You have other ways to check email adress. Check out this post, it may be interesting: What is the best Java email address validation method?

edited May 23 '17 at 12:00

Community

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answered Mar 22 '17 at 00:09

User9123

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do you want to teach people to use variable names like `_at_Index` ? – Scary Wombat Mar 22 '17 at 00:25
`if (_at_Index < 0` is an email starting with an `@` correct? – Scary Wombat Mar 22 '17 at 00:26
@ScaryWombat sorry for the `_at_Index` ! I wanted to make it clear that "at" means "@" – User9123 Mar 22 '17 at 00:31
@ScaryWombat `indexOf` returns -1 when the caracter is not found (check out the documentation). And yes this code only check this specification : "address contains a @ and a . after the @" – User9123 Mar 22 '17 at 00:33
Yes, I agree that if it is returns `-1` it is an error, but what about if the value is `0` ? – Scary Wombat Mar 22 '17 at 00:34
I forgot to check if there is no spaces... – User9123 Mar 22 '17 at 00:36
with your code, does this pass ? `@User9123.gmail.com` – Scary Wombat Mar 22 '17 at 00:38
@ScaryWombat `I have to verify that all emails have '@' and '.' and don't have a space.` is the specification I implemented. In fact I even didn't had to use `atIndex`. – User9123 Mar 22 '17 at 00:40

invalid email address string check (for school)

1 Answers1