JSF 自定义验证器：h：消息未呈现

Question

I have the following FacesValidator:

@RequestScoped
@FacesValidator("passwordValidator")
public class PasswordValidator implements Validator {

    @PersistenceUnit(unitName = "TradeCenterPU")
    private EntityManagerFactory emf;

    @Override
    public void validate(final FacesContext context, final UIComponent comp, final Object values) throws ValidatorException {
        String password = (String)values;
        System.out.println("passwordValidator():" + password);
        EntityManager em = emf.createEntityManager();
        Query q = em.createNamedQuery("user.findByUsername");
        q.setParameter("username", context.getExternalContext().getRemoteUser());
        User user = (User)q.getSingleResult();
        String pwhash = DigestUtils.md5Hex(password + user.getSalt());
        System.out.println("User: " + user.getUsername() + ", PwHash: " + pwhash + ", Password: " + user.getPassword());

        if (!pwhash.equals(user.getPassword())) {
            System.out.println(comp.getClientId(context) + ": Old password is wrong!");
            FacesMessage msg = new FacesMessage(
                    FacesMessage.SEVERITY_ERROR,
                    "The old password was not entered correctly.",
                    ""
            );
            context.addMessage(comp.getClientId(context), msg);
            throw new ValidatorException(msg);
        }
    }
}

Wich gets used in the following way:

<h:form id="profileform" action="#{userController.updatePassword}">
    <h:messages errorClass="error_message" globalOnly="true"/>
    ...
    <h:outputLabel for="password" value="Old password:" />
    <h:inputSecret id="password" name="password" label="Old password">
        <f:validateLength minimum="8" maximum="15" />
        <f:validator validatorId="passwordValidator"/>
    </h:inputSecret>
    <h:message for="password" errorClass="error_message"/>
    ...
</h:form>

The problem now is, that the message which the Validator generates is never displayed. I know it gets generated, because in the Glassfish-Log I can see

profileform:password: Old password is wrong!

I can't see any error in this especially since the message for the f:validateLength gets displayed if the password is to long or to short. If I do

context.addMessage(null, msg);

instead of

context.addMessage(comp.getClientId(context), msg);

the Message is shown in the h:messages component. Has anyone an idea? Thanks in advance

Answer 1

You see nothing, because you've constructed the FacesMessage with a summary and a detail. When the detail is not null , then it will be displayed instead. Since you've set it with an empty string, you "see" an empty message. You basically need to set detail to null to get the summary to display.

But this isn't exactly the way you're supposed to set a message on a validation error. You should just throw the ValidatorException and JSF will add the in the ValidatorException constructed message to the context itself based on the component's client ID.

So, you need to replace

FacesMessage msg = new FacesMessage(
        FacesMessage.SEVERITY_ERROR,
        "The old password was not entered correctly.",
        ""
);
context.addMessage(comp.getClientId(context), msg);
throw new ValidatorException(msg);

by

String msg = "The old password was not entered correctly.";
throw new ValidatorException(new FacesMessage(msg));

and it will work as you expect.