How to display my application's errors in JSF?

Question

In my JSF/Facelets app, here\'s a simplified version of part of my form:

Answer 1

Found this while Googling. The second post makes a point about the different phases of JSF, which might be causing your error message to become lost. Also, try null in place of "newPassword" because you do not have any object with the id newPassword.

Answer 2

Simple answer, if you don't need to bind it to a specific component...

Java:

            FacesMessage message = new FacesMessage(FacesMessage.SEVERITY_ERROR, "Authentication failed", null);
            FacesContext context = FacesContext.getCurrentInstance();
            context.addMessage(null, message);      

XHTML:

            <h:messages></h:messages>

Answer 3

FacesContext.addMessage(String, FacesMessage) requires the component's clientId, not it's id. If you're wondering why, think about having a control as a child of a dataTable, stamping out different values with the same control for each row - it would be possible to have a different message printed for each row. The id is always the same; the clientId is unique per row.

So "myform:mybutton" is the correct value, but hard-coding this is ill-advised. A lookup would create less coupling between the view and the business logic and would be an approach that works in more restrictive environments like portlets.

<f:view>
  <h:form>
    <h:commandButton id="mybutton" value="click"
      binding="#{showMessageAction.mybutton}"
      action="#{showMessageAction.validatePassword}" />
    <h:message for="mybutton" />
  </h:form>
</f:view>

Managed bean logic:

/** Must be request scope for binding */
public class ShowMessageAction {

    private UIComponent mybutton;

    private boolean isOK = false;

    public String validatePassword() {
        if (isOK) {
            return "ok";
        }
        else {
            // invalid
            FacesMessage message = new FacesMessage("Invalid password length");
            FacesContext context = FacesContext.getCurrentInstance();
            context.addMessage(mybutton.getClientId(context), message);
        }
        return null;
    }

    public void setMybutton(UIComponent mybutton) {
        this.mybutton = mybutton;
    }

    public UIComponent getMybutton() {
        return mybutton;
    }
}

Answer 4

In case anyone was curious, I was able to figure this out based on all of your responses combined!

This is in the Facelet:

<h:form id="myform">
  <h:inputSecret value="#{createNewPassword.newPassword1}" id="newPassword1" />
  <h:message class="error" for="newPassword1" id="newPassword1Error" />
  <h:inputSecret value="#{createNewPassword.newPassword2}" id="newPassword2" />
  <h:message class="error" for="newPassword2" id="newPassword2Error" />
  <h:commandButton value="Continue" action="#{createNewPassword.continueButton}" />
</h:form>

This is in the continueButton() method:

FacesContext.getCurrentInstance().addMessage("myForm:newPassword1", new FacesMessage(PASSWORDS_DONT_MATCH, PASSWORDS_DONT_MATCH));

And it works! Thanks for the help!

Answer 5

Remember that:

FacesContext context = FacesContext.getCurrentInstance();
context.addMessage( null, new FacesMessage( "The message to display in client" ));            

is also valid, because when null is specified as first parameter, it is applied to the whole form.

More info: coreservlets.com //Outdated

Answer 6

You also have to include the FormID in your call to addMessage().

 FacesContext.getCurrentInstance().addMessage("myform:newPassword1", new FacesMessage("Error: Your password is NOT strong enough."));

This should do the trick.

Regards.