RequestParameter versus <param>

[trincao]

Hi Seam experts!

I have a question for you.
What are the differences between using the @RequestParameter annotation and <param /> on pages.xml?
I know they are supposed to be the same, but I have detected some differences between them.

For instance:

Setting the <page /> tag on pages.xml it sets the serviceId variable via the setter



`
  <page view-id="/service_show.xhtml" action="#{serviceSearch.doSetSelectedService}">
    <param name="srvid" value="#{serviceSearch.serviceId}" />
    <navigation>
      <rule if-outcome="addComment">
        <redirect view-id="/service_show.xhtml" />
      </rule>
    </navigation>
  </page>
`


Whereas using @RequestParameter, the serviceId is set directly (not via the setter):

`
        @RequestParameter(value = "srvid")
        String serviceId;
`


Another difference is that when using @RequestParameter with the following form I get the exception bellow, whereas using <param /> it works fine.
It seems that when using @RequestParameter the variable is set later thant when using <param />.

`
  <h:form id="addServiceCommentForm">
    <h:inputTextarea id="comments" value="#{serviceSearch.newServiceComment.text}" />
    <br />
    <h:commandLink id="submit" value="Create" action="#{serviceSearch.createServiceComment}">
    </h:commandLink>
  </h:form>
`

What are there other differences? Have you got an idea why this is happening?
Thank you for your time.

Gonçalo

2008-08-29 19:08:54,764 FATAL [javax.enterprise.resource.webcontainer.jsf.application] java.lang.NumberFormatException: null
javax.faces.el.EvaluationException: java.lang.NumberFormatException: null
        at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:91)
        at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:91)
        at javax.faces.component.UICommand.broadcast(UICommand.java:383)
        at org.ajax4jsf.component.AjaxViewRoot.processEvents(AjaxViewRoot.java:184)
        at org.ajax4jsf.component.AjaxViewRoot.broadcastEvents(AjaxViewRoot.java:162)
        at org.ajax4jsf.component.AjaxViewRoot.processApplication(AjaxViewRoot.java:350)
        at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:97)
        at com.sun.faces.lifecycle.LifecycleImpl.phase(LifecycleImpl.java:251)
...
Caused by: java.lang.NumberFormatException: null
        at java.lang.Long.parseLong(Long.java:372)
        at java.lang.Long.parseLong(Long.java:461)
        at com.something.portal.web.ServiceSearchAction.createServiceComment(ServiceSearchAction.java:115)

[gjeudy]

Your exception might be because no value is being set? i.e. RequestParameter is not being propagated ?

<h:commandLink id="submit" value="Create" action="#{serviceSearch.createServiceComment}">
    </h:commandLink>

you don't put a parameter on your commandLink so I don't see how you can have the request parameter set while executing createServiceComment. You can try setting it in pages.xml or use f:param tag inside commandLink.

[pmuir]

Goncalo Trincao wrote on Aug 29, 2008 20:31:


What are the differences between using the @RequestParameter annotation and <param /> on pages.xml?
I know they are supposed to be the same, but I have detected some differences between them.

No, they are not supposed to be the same, read the docs more carefully.