JSF - Passing Parameters to a view on click of Button

Question

I am using JSF 2.0 and have a simple TestButton.xhtml like below:

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN"     
 "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<ui:composition xmlns="http://www.w3.org/1999/xhtml" 
  xmlns:ui="http://java.sun.com/jsf/facelets" 
  xmlns:f="http://java.sun.com/jsf/core" 
  xmlns:h="http://java.sun.com/jsf/html"
  xmlns:a4j="http://richfaces.org/a4j"
  xmlns:rich="http://richfaces.org/rich">

<h:body>
<h:form>
        <h:inputText value="#{employee.empName}"/><br/>
        <h:commandButton value="Derive" action="EmployeeTest2" >
            <f:param name="Name" value="#{employee.empName}"/>
        </h:commandButton>  
</h:form>
</h:body>
</ui:composition>

And a Managed bean which is view scoped.

@ManagedBean(name="employee", eager=true)
@ViewScoped
public class Employee implements Serializable{

String empName;
String selectedEmployeeName;


public String getSelectedEmployeeName() {
    return selectedEmployeeName;
}
public void setSelectedEmployeeName(String selectedEmployeeName) {
    this.selectedEmployeeName = selectedEmployeeName;
}

public Employee() {
    super();
}

public String getEmpName() {
    return empName;
}
public void setEmpName(String empName) {
    this.empName = empName;
}
public void manipulate(){
    System.out.println("Manipulate called...");
    System.out.println(selectedEmployeeName);
    this.selectedEmployeeName = this.selectedEmployeeName + " Jr.";
}

Now on click of button, i navigate to EmployeeTest2.xhtml which has following code :

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN"  
 "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<ui:composition xmlns="http://www.w3.org/1999/xhtml" 
  xmlns:ui="http://java.sun.com/jsf/facelets" 
  xmlns:f="http://java.sun.com/jsf/core" 
  xmlns:h="http://java.sun.com/jsf/html"
  xmlns:a4j="http://richfaces.org/a4j"
  xmlns:rich="http://richfaces.org/rich">

<f:view>
    <f:metadata>
        <f:viewParam name="Name" value="#{employee.selectedEmployeeName}"/>
        <f:event type="preRenderView" listener="#{employee.manipulate}"/>
    </f:metadata>
</f:view>

<h:body>
        <h:inputText value="#{employee.selectedEmployeeName}"/>
</h:body>   
</ui:composition>

i get correctly navigated to EmployeeTest2.xhtml but my parameter value is coming as null. I can see that manipulate method is getting called(sysouts get printed) but selectedEmployeeName is null.

Please advise as to what am i missing.

I already referred to below thread and did same but of no help.

https://stackoverflow.com/questions/20880027/passing-parameters-to-a-view-scoped bean-in-jsf

Update 1: Changed

  <h:inputText value="Chris"/>

to <h:inputText value="#{employee.empName}"/>

Put a breakpoint at setter method for selectedEmployee. Setter is not getting called which means param passing is not working.

Update 2 Please see updated testButton.xhtml

?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN"    
  "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<ui:composition xmlns="http://www.w3.org/1999/xhtml" 
  xmlns:ui="http://java.sun.com/jsf/facelets" 
  xmlns:f="http://java.sun.com/jsf/core" 
  xmlns:h="http://java.sun.com/jsf/html"
  xmlns:a4j="http://richfaces.org/a4j"
  xmlns:rich="http://richfaces.org/rich">

<h:body>
<h:form>
        <h:inputText name = "Name" value="#{employee.empName}"/><br/>
        <h:commandButton value="Submit" action="EmployeeTest2" >
            <f:param name="Name" value="#{employee.empName}"/>
        </h:commandButton>  
</h:form>
</h:body>
</ui:composition>

Maciej Kowalski · Answer 1 · 2017-01-20T18:30:40.353

0

The code seems correct, in my opinion you are sending null to the next page because the value of the employee.empName is actually null.

I would debug the getEmpName() method when the TestButton.xhtml is loaded and then additionally check, after you click the button and move on to the next page whether the parameter is present in the url.

UPDATE

Ok the param is actually the value of the input. In that case add name to its definition. You form should look like this:

<h:inputText name="Name" value="#{employee.empName}"/><br/>
<h:commandButton value="Derive" action="EmployeeTest2" />

UPDATE 2

This is a workaround but you can also try this:

@PostConstruct
      public void postConstruct(){

      Map<String,String> params = FacesContext.getCurrentInstance().getExternalContext().getRequestParameterMap();
      setSelectedEmployeeName(params.get("Name"));
}

edited Jan 20 '17 at 18:30

answered Jan 19 '17 at 16:08

Maciej Kowalski

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Please see update 1 – true_programmer Jan 20 '17 at 17:32
Please check my updated post – Maciej Kowalski Jan 20 '17 at 17:54
@ Maciej Kowalski: Did the same but of no help. Still showing up as null. Please see update 2 – true_programmer Jan 20 '17 at 18:03
Ok, is this method invoked? listener="#{employee.manipulate} – Maciej Kowalski Jan 20 '17 at 18:24
Yes, it was invoked. – true_programmer Jan 20 '17 at 18:58
I will do some more tests.. try the alternative solution i have just added in the meantime – Maciej Kowalski Jan 20 '17 at 19:01
I am using the same in request and response pages. Post construct will run only once when the bean is created. Isn't it? – true_programmer Jan 20 '17 at 19:23
No. ViewScope only lives on one screen, if you go to the next a new instnance will be created (even though its the same bean class that is used by the next view) – Maciej Kowalski Jan 20 '17 at 19:27
Thank you that's what i thought. I thought if i am passing the bean's value as param, may be it will keep it in scope of next view as well..Thank you for the clarification though. I will wait for your answer.. – true_programmer Jan 20 '17 at 20:11

JSF - Passing Parameters to a view on click of Button

1 Answers1