public class User {
@NotNull
private String username;
@Pattern(regexp = "^\\w+@[a-zA-Z_]+?\\.[a-zA-Z]{2,3}$")
private String email;
// Getters and Setters
}
public class ValidatorService {
public static void main(String[] args) {
User user = new User();
user.setUsername("John");
user.setEmail("john@example.com");
Validator validator = Validation.buildDefaultValidatorFactory().getValidator();
Set<ConstraintViolation<User>> violations = validator.validate(user);
for (ConstraintViolation<User> violation : violations) {
System.out.println(violation.getMessage());
}
}
}
