Inputting and validating the email address in JAVA

Question

I have written the below code but i am unable to make it loop if the input entered is false.Kindly help me.

System.out.println("Please enter your email address ex:xyz@gmail.com");
        String emailaddress=name.nextLine();

        String email_regex = "[A-Z]+[a-zA-Z_]+@\b([a-zA-Z]+.){2}\b?.[a-zA-Z]+";
        String testString = emailaddress;
        Boolean b = testString.matches(email_regex);
        System.out.println("String: " + testString + " :Valid = " + b);
        System.out.println("Email address is " +emailaddress);

Using console input: [Java: How to get input..][1] [1]: http://stackoverflow.com/questions/4644415/java-how-to-get-input-from-system-console — Oskars Pakers, Nov 27 '14 at 15:04
What do you mean by loop? Where do you want to go when the email address if false or true? — We are Borg, Nov 27 '14 at 15:05
@akshay: the above code just takes input of email addressvfrom the user and prints if true,but if its false its not going back and asking for email address again.. — Vdev, Nov 27 '14 at 15:07
I will write an answer, using functions, see if that makes it easys. — We are Borg, Nov 27 '14 at 15:08
please remember StackOverflow is not a code generator site. These type of questions are not suitable for this site. — Sikorski, Nov 27 '14 at 20:40

Bruce_Wayne · Answer 1 · 2014-11-27T15:31:57.387

0

   boolean b;
   do {
        System.out.println("Please enter your email address ex:xyz@gmail.com");
        String emailaddress=name.nextLine();
        String email_regex = "[A-Z]+[a-zA-Z_]+@\b([a-zA-Z]+.){2}\b?.[a-zA-Z]+";
        String testString = emailaddress;
        b = testString.matches(email_regex);
        System.out.println("String: " + testString + " :Valid = " + b);
        System.out.println("Email address is " +emailaddress);
    }while(!b);

edited Nov 27 '14 at 15:31

answered Nov 27 '14 at 15:08

Bruce_Wayne

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Hi its going back to the loop even if correct input is given...:( – Vdev Nov 27 '14 at 15:50
check the email u have entered, loop will break as soon as 'b' contains 'true' value, CAREFULLY re-examine the code and the email u are using for testing. – Bruce_Wayne Nov 27 '14 at 15:55
yes loop is breaking once true value is entered but instead of coming out of the loop its rather displaying "please enter your email address" again – Vdev Nov 27 '14 at 16:01

Salih Erikci · Answer 2 · 2014-11-27T16:31:13.647

0

    String testString;
    String emailaddress;
    boolean b = false;

    do {
        System.out.println("Please enter your email address ex:xyz@gmail.com");
        Scanner name = new Scanner(System.in);
        emailaddress = name.nextLine();

        String email_regex = "^[_A-Za-z0-9-\\+]+(\\.[_A-Za-z0-9-]+)*@"
    + "[A-Za-z0-9-]+(\\.[A-Za-z0-9]+)*(\\.[A-Za-z]{2,})$";
        testString = emailaddress;
        b = testString.matches(email_regex);
        System.out.println("String: " + testString + " :Valid = " + b);
    } while (!b);

    System.out.println("Email address is " + emailaddress);

edited Nov 27 '14 at 16:31

answered Nov 27 '14 at 15:09

Salih Erikci

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Boolean b needs to be out of do while – Sikorski Nov 27 '14 at 15:28
i am getting in 2 lines Boolean b = testString.matches(email_regex); System.out.println("Email address is "+testString);--one is (b is a duplicate local varaible and the other is teststring canot be resolved as a varaibe...kindly help – Vdev Nov 27 '14 at 15:36
@NandithaVasudev Edit your code as i show in my answer. – Salih Erikci Nov 27 '14 at 16:13
i have edited it displays this way even though i have entered the correct email Please enter your email address ex:xyz@gmail.com nanditha22@gmail.com String: nanditha22@gmail.com :Valid = false Please enter your email address ex:xyz@gmail.com – Vdev Nov 27 '14 at 16:25
Your regex is wrong.I used the regex from http://www.mkyong.com/regular-expressions/how-to-validate-email-address-with-regular-expression/ and it worked fine. See my edited answer with this regex. – Salih Erikci Nov 27 '14 at 16:31

We are Borg · Accepted Answer · 2014-11-27T16:52:19.287

Here goes the 3 functions :

public class abc{

public static void main(String[] args){
   inputEmail();
}

public boolean checkEmailvalidity(String emailaddress){
    String email_regex = "[A-Z]+[a-zA-Z_]+@\b([a-zA-Z]+.){2}\b?.[a-zA-Z]+";
   boolean b = testString.matches(email_regex);
   return b;
}

public void inputEmail(){
        System.out.println("Please enter your email address ex:xyz@gmail.com");
        String emailaddress=name.nextLine();
        boolean a = checkEmailvalidity(emailaddress);
       if(a){
          System.out.println("Valid email");
        } else {
          System.out.println("InValid email");
           inputEmail();
       }
}

}

here is with your updated answer :

package smsmain; 
import java.util.Scanner; 
     public class CStudentinfo { 
        public static void createstudent() { 
          Scanner name = new Scanner(System.in); 
          System.out.println("Please enter your first name:");     
             while(!name.hasNext("[a-zA-Z]+")){ 
                 System.out.println("Please re-enter your name, use alphabets)
                  System.out.println("Please enter your first name:"); 
                   name.nextLine(); 

              } 
        String firstname=name.nextLine(); 
        System.out.println("Your firstname is " + firstname); 
       inputEmail();

Inputting and validating the email address in JAVA

3 Answers3