JSF commandButton with Parameters

Question

Hello,
How can I pass parameters to backing bean through commandButton?

Answer 1

Could you pl tell me how to pass parameter thru CommandButton
I have the following situation
1) greetingList.faces which list the Ids & greeting Text
Id Text
1 Hello World
2 Hello World
2) Pl note Ids are h:commandLink. A click on the Id will render greetingForm.faces with data pertaining to that Id and with Update h:CommandButton
3) When i click Update button it results in the following error
javax.faces.FacesException: Error calling action method of component with id greetingForm:_id4
Caused by: javax.faces.el.EvaluationException: Exception while invoking expression #{greetingForm.update}
Caused by: java.lang.NullPointerException
So i verified with h:message that Id is passed as Null when click on Update button. I also checked greetingForm.faces has a not null value by printing <h:outputText value="#{greetingForm.message.id}"/>
So i guess the Id value is overwriteen with null. Also i have defined Id as property in managed bean
<managed-bean-name>greetingForm</managed-bean-name>
<managed-bean-class>com.mycompany.GreetingForm</managed-bean-class>
<managed-bean-scope>request</managed-bean-scope>
<managed-property>
<property-name>id</property-name>
<value>#{param.id}</value>
</managed-property>
Any pointers/suggestions at the earliest on how to pass the value of Id on a click of update button from greetingForm.faces to greetingForm.java will be highly appreciated
I am willing to upload my war file
Regards
Bansi