public class User {
@NotNull
@Size(min = 3, max = 20)
private String name;
@NotEmpty
@Email
private String email;
}
public class Main {
public static void main(String[] args) {
User user = new User();
user.setName("John");
user.setEmail("john@example.com");
ValidatorFactory factory = Validation.buildDefaultValidatorFactory();
Validator validator = factory.getValidator();
Set<ConstraintViolation<User>> violations = validator.validate(user);
if (violations.isEmpty()) {
System.out.println("User data is valid.");
} else {
System.out.println("User data is invalid.");
for (ConstraintViolation<User> violation : violations) {
System.out.println(violation.getPropertyPath() + ": " + violation.getMessage());
}
}
}
}
