javax.validation.constraints.Email in SpringBoot

Question

I have a bean with this validation:

@Email(message = "Email is not valid", regexp="{(?:[a-z0-9!#$%&'*+/=?^_`{|}~-]+(?:\\.[a-z0-9!#$%&'*+/=?^_`{|}~-]+)*|\"(?:[\\x01-\\x08\\x0b\\x0c\\x0e-\\x1f\\x21\\x23-\\x5b\\x5d-\\x7f]|\\\\[\\x01-\\x09\\x0b\\x0c\\x0e-\\x7f])*\")@(?:(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\\.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])?|\\[(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?|[a-z0-9-]*[a-z0-9]:(?:[\\x01-\\x08\\x0b\\x0c\\x0e-\\x1f\\x21-\\x5a\\x53-\\x7f]|\\\\[\\x01-\\x09\\x0b\\x0c\\x0e-\\x7f])+)\\])}")
@NotEmpty(message = "Email cannot be empty")
private String email;

when the email is empty the message is fine, but when I enter this text

perisava.util.Random@1d7f0036

no error is shown

Answer 1

javax.validation.constraints.Email annotation depends on Jakarta Bean Validation providers for validation. Hibernate Validator is the only compliant validator for this. By default hibernate vaildator matches the email to regex .* unless you provide the regex yourself. Hibernate email validator source code is here.

One solution is to provide your own email regex

@Email(message = "Email is not valid", regexp = "^[a-zA-Z0-9_!#$%&'*+/=?`{|}~^.-]+@[a-zA-Z0-9.-]+$")
@NotEmpty(message = "Email cannot be empty")
private String email;

The official standard is RFC 5322. But it does not cover all cases for modern emails. You can find more solutions here. Even then regex would be up to you to decide.