@FacesValidator(value = "validator.CustomValidator1", managed = true)
public class CustomValidator1 implements Validator<String> {
   ...
}
@FacesValidator(value = "validator.CustomValidator2", managed = true)
public class CustomValidator2 implements Validator<String> {
   ...
}

                <h:inputText id="input-value" value="#{customBean.inputValue}">
                  <f:validator validatorId="validator.CustomValidator2" />
                  <f:validator validatorId="validator.CustomValidator1" />
                </h:inputText>