jsf2视图参数和viewscoped bean

Question

How can I access the view parameters from a viewscoped bean?
I have a page almost with the same content as this:

<f:metadata>
    <f:viewParam name="name" value="#{goToUserpageRequest.name}" />
</f:metadata>

<ui:define name="content">
    <h:outputText value="#{user.name}" styleClass="text"></h:outputText>
    <h:outputText value="#{user.description}" styleClass="text"></h:outputText>
</ui:define>

GoToUserpageRequest is a bean which I use to redirect to this page, so I can send the value for name.
User is my viewscoped bean. I want to pass the value of viewParam name to user.name. How can I do that?
Thanks in advance!

Answer 1

There is an easier way for your case which I have just figured out while looking for a solution for the same situation. just use this in your xhtml together :

<f:metadata>
    <f:viewParam name="name" value="#{goToUserpageRequest.name}" />
</f:metadata>

 <f:event type="preRenderView" listener="#{MY_BEAN.setName(goToUserpageRequest.name)}"/>

so you can send the goToUserpageRequest.name value back to your redirected view's bean (I called MY_BEAN)

Answer 2

You can get this information using the external context from your context . See the request parameters .

However, I would try to use a request scope bean and inject the view and parameter scope values into that. You can then manipulate your view scoped object from there. This approach is easier to unit test.

---

EDIT:

Here is a sample implementation:

@ManagedBean @RequestScoped
public class NameUpdater {
    @ManagedProperty("#{param.name}") private String name;
    public String getName() { return name; }
    public void setName(String name) { this.name = name; }

    @ManagedProperty("#{user}") private User user;
    public User getUser() { return user; }
    public void setUser(User user) { this.user = user; }

    @PostConstruct public void init() {
        if(name != null) user.setName(name);
    }
}

In order to create the request scoped bean, the binding expression would change to something like:

<h:outputText value="#{nameUpdater.user.name}" />