<dependency>
<groupId>javax.validation</groupId>
<artifactId>validation-api</artifactId>
<version>2.0.1.Final</version>
</dependency>
public class User {
private String username;
private int age;
}
ValidatorFactory factory = Validation.buildDefaultValidatorFactory();
Validator validator = factory.getValidator();
User user = new User();
user.setUsername("John");
user.setAge(20);
Set<ConstraintViolation<User>> violations = validator.validate(user);
if (violations.isEmpty()) {
} else {
for (ConstraintViolation<User> violation : violations) {
System.out.println(violation.getMessage());
}
}
