Java regex email

Question

First of all, I know that using regex for email is not recommended but I gotta test this out.

I have this regex:

\\b[A-Z0-9._%-]+@[A-Z0-9.-]+\\.[A-Z]         


        

Answer 1

Regex for Facebook-like validation:

public static final String REGEX_EMAIL_VALIDATION = "^[\\w-\\+]+(\\.[\\w]+)*@[\\w-]+(\\.[\\w]+)*(\\.[a-zA-Z]{2,})$";

Dto for Unit tests(with Lombok):

@Data
@Accessors(chain = true)
@FieldDefaults(level = AccessLevel.PRIVATE)
public class UserCreateDto {

    @NotNull
    @Pattern(regexp = REGEX_EMAIL_VALIDATION)
    @Size(min = 1, max = 254)
    String email;
}

Valid/invalid emails below with Unit tests:

public class UserCreateValidationDtoTest {

private static final String[] VALID_EMAILS = new String[]{"email@yahoo.com", "email-100@yahoo.com",
        "Email.100@yahoo.com", "email111@email.com", "email-100@email.net",
        "email.100@email.com.au", "emAil@1.com", "email@gmail.com.com",
        "email+100@gmail.com", "emAil-100@yahoo-test.com", "email_100@yahoo-test.ABC.CoM"};
private static final String[] INVALID_EMAILS = new String[]{"あいうえお@example.com", "email@111",
        "email", "email@.com.my", "email123@gmail.", "email123@.com", "email123@.com.com",
        ".email@email.com", "email()*@gmAil.com", "eEmail()*@gmail.com", "email@%*.com", "email..2002@gmail.com",
        "email.@gmail.com", "email@email@gmail.com", "email@gmail.com."};
private Validator validator;

@Before
public void setUp() throws Exception {
    ValidatorFactory factory = Validation.buildDefaultValidatorFactory();
    validator = factory.getValidator();
}

@Test
public void emailValidationShouldBeValid() throws Exception {
    Arrays.stream(VALID_EMAILS)
            .forEach(email -> {
                        Set> violations = validateEmail(
                                new UserCreateDto().setEmail(email));
                        System.out.println("Email: " + email + ", violations: " + violations);
                        Assert.assertTrue(violations.isEmpty());
                    }
            );
}

@Test
public void emailValidationShouldBeNotValid() throws Exception {
    Arrays.stream(INVALID_EMAILS)
            .forEach(email -> {
                        Set> violations = validateEmail(
                                new UserCreateDto().setEmail(email));
                        System.out.println("Email: " + email + ", violations: " + violations);
                        Assert.assertTrue(!violations.isEmpty());
                    }
            );
}


private Set> validateEmail(UserCreateDto user) {
    String emailFieldName = "email";
    return validator.validateProperty(user, emailFieldName);
}

}