URL Param + ManagedBean + form submit Question

Question

Hey,
I have a managed bean and configured the bean so that i takes params from the url and sets them automatically. The bean parameter is a integer value.
So when i call samplePage.faces?param1=23 then the bean takes the parameter from the url and i can query the database and present the result. That works perfekt
My problem is now the following:
On this page i have a form and some input tags to edit values, and now i want to submit the form and update the record in the database. (The record is identified by the url param)
But when i submit my form i got a java.lang.IllegalArgumentException - java.lang.IllegalArgumentException exception.
I thing that is because the action of the form has this parameter not ( action=samplePage.faces without my param) and when the bean tries to get the param from the url, which is not existing, then the exception is thrown.
Any suggestions what i can do?

Answer 1

i assume you have 2 managed beans that are in request scope. one bean for the overview page, one for the details page.
overview page:
create the link with the h:outputlink component which has one nested h:outputtext (the link text) and several nested f:param components. that means, you write one f:param for every parameter you want to pass to your details page. in your example, this would be only the id.
... so now you click the link ...
details page:
the id-parameter is available in the field "myId" in your details bean via this entry in faces-config.xml:
<managed-bean>
          <managed-bean-name>details</managed-bean-name>
          <managed-bean-class>com.DetailsBean</managed-bean-class>
          <managed-bean-scope>request</managed-bean-scope>
          <managed-property>
               <property-name>myId</property-name>
               <value>#{param.id}</value>
          </managed-property>
     </managed-bean>In DetailsBean, first you have to retrieve the data from the database. This could be done in the constructor or in a method annotated with @PostConstruct.
Also, save the id in a h:inputhidden. You will need the id again in the next step.
... now the user edits the data and presses submit ...
(All Parameters are lost at this point.) In your action, read the id from the h:inputhidden field. Now you have everything to update your database entry.