JSF Action Method not being called

问题:

I have a JSF view with a Primefaces data table and a command button insite it, as fallows:

<p:messages id="statusMessages" showDetail="true" />
    <h:form id="listForm">
        <p:panel header="Wellsite List">
            <br />
            <h:outputLabel value="Welcome, #{wellsiteController.loggedUser.login}" />
            <br />
            <br />

            <p:dataTable id="dataTable" var="wellsite" value="#{wellsiteController.wellsiteDataTableModel}"
                         paginator="true" rows="10" selection="#{wellsiteController.wellsite}">

                <p:column selectionMode="single" style="width:18px" id="radioSelect" />

                <p:column sortBy="#{wellsite.reference}" headerText="Wellsite ID">
                    <h:outputText value="#{wellsite.reference}" />
                </p:column>

                <p:column headerText="Allowed Groups">
                    <h:outputText value="#{wellsite.allowedGroups.toString()}" />
                </p:column>

                <f:facet name="footer">
                    <h:panelGrid columns="3">
                        <p:commandButton id="addWellsite" value="Add New Wellsite" icon="ui-icon-flag" ajax="false" action="#{wellsiteController.showAddWellsite}"/>
                        <p:commandButton id="editWellsite" value="Edit Selected Wellsite" icon="ui-icon-wrench" ajax="false" action="#{wellsiteController.showEditWellsite}"/>

                        <p:commandButton id="deleteWellsiteButton" value="Remove Selected Wellsite" icon="ui-icon-trash" onclick="confirmation.show()" type="button"/>

                    </h:panelGrid>
                </f:facet>
            </p:dataTable>
            <p:spacer height="20" />
        </p:panel>
        <p:confirmDialog id="confirmDialog" message="Are you sure you want to remove the selected Wellsite along with all it's data?" header="Confirmation" severity="alert" widgetVar="confirmation">  
            <p:commandButton id="confirm" value="Yes" ajax="false" oncomplete="confirmation.hide()" action="#{wellsiteController.deleteWellsite}" />
            <p:commandButton id="decline" value="Cancel" onclick="confirmation.hide()" type="button" />   

        </p:confirmDialog>
    </h:form>

And here's the controller:

@ManagedBean(name = "wellsiteController")
@RequestScoped
public class WellsiteController implements Serializable {
private static final long serialVersionUID = 1L;

@ManagedProperty("#{wellsiteDao}")
private WellsiteDao wellsiteDao;

@ManagedProperty("#{userDao}")
private UserDao userDao;

@ManagedProperty("#{groupDao}")
private GroupDao groupDao;

@ManagedProperty("#{userController.loggedUser}")
private UserEnt loggedUser;

private WellsiteEnt wellsite;
private List<WellsiteEnt> wellsiteList;
DualListModel<GroupEnt> pickGroupsModel;

public WellsiteController(){
}

@PostConstruct
public void build(){
    wellsite = new WellsiteEnt();
    wellsite.setAllowedGroups(new ArrayList<GroupEnt>());
}

/*some getters & setters*/

public WellsiteDataTableModel getWellsiteDataTableModel(){
    return new WellsiteDataTableModel(getWellsiteList());
}

public void setPickGroupsModel(DualListModel<GroupEnt> model){
    pickGroupsModel = model;
}

public DualListModel<GroupEnt> getPickGroupsModel() {
    if(pickGroupsModel == null){
        List<GroupEnt> allGroups = groupDao.getAll();
        List<GroupEnt> currentGroups = wellsite.getAllowedGroups();
        for(GroupEnt g : currentGroups){
            allGroups.remove(g);
        }
        pickGroupsModel = new DualListModel<GroupEnt>(allGroups, currentGroups);
    }
    return pickGroupsModel;
}

public String listWellsites(){
    getWellsiteList();
    return "listWellsites";
}

public String showAddWellsite(){
    FacesContext context = FacesContext.getCurrentInstance();
    setWellsite(new WellsiteEnt());
    wellsite.setAllowedGroups(new ArrayList<GroupEnt>());
    pickGroupsModel = null;
    context.addMessage(null, new FacesMessage(FacesMessage.SEVERITY_INFO,
                                            "Fields annotated with a ' * ' are mandatory",""));
    return "addWellsite";
}

public String addWellsite(){
    FacesContext context = FacesContext.getCurrentInstance();

    wellsite.setDate(new Date());
    wellsite.setLastUpdate(wellsite.getDate());
    try {
        wellsiteDao.addWell(wellsite);

        for(GroupEnt g : pickGroupsModel.getTarget()){
            GroupEnt group = groupDao.getOne(g.getGroupId());
            group.getGroupWellsites().add(wellsite);
            groupDao.update(group);
        }
        return listWellsites();

    } catch (Exception ex) {
        Logger.getLogger(WellsiteController.class.getName()).log(Level.SEVERE, null, ex);
        context.addMessage(null, new FacesMessage(FacesMessage.SEVERITY_ERROR,
                                            ex.getMessage(),""));
        return null;
    }
}
}

This view gets rendered correctly. The datatable and buttons looks fine. The problem is that when first i click the "addWellsite" commandButton, nothing happens. The page just seems to refresh. If i click it again, as exception happens:

java.lang.NumberFormatException: For input string: "null"

Using a debugger, i found out that the "addWellsite"'s action is NOT called the first time, and so, not outcome is generated (thus, the page refresh).

The exception is probably comming from the lack of initialization in the current or the target views (since both view are displayed from action methods that were not called in the page refresh)

The question is: WHY the action method is not called the first time?

As from this answer:

Whenever an UICommand component fails to invoke the associated action, verify the following:

1. UICommand components must be placed inside an UIForm component (e.g. h:form).

I do have a h:form

2. You cannot nest multiple UIForm components in each other (watch out with include files!).

There's only one.

3. No validation/conversion error should have been occurred (use h:messages to get them all).

I have a h:messages that does not display any error.

4. If UICommand components are placed inside an UIData component, ensure that exactly the same DataModel (the object behind the UIData's value attribute) is preserved.

The commandButton is inside the dataTable, but the target view does not need the dataModel. As my controller code shows, the object is built as the view tries to retrive it. The next request is not using this dataTable, to i do not handle it anymore.

5. The rendered and disabled attributes of the component and all of the parent components should not evaluate to false during apply request values phase.

There's no rendered or disbled attributes.

6. Be sure that no PhaseListener or any EventListener in the request-response chain has changed the JSF lifecycle to skip the invoke action phase.

No phaseListener is defined.

7. Be sure that no Filter or Servlet in the same request-response chain has blocked the request fo the FacesServlet somehow.

No other Servlet is defined. I don't even know what a Filter is.

WHY the action method is not called the first time?

回答1:

This can happen when a parent of this <h:form> was been rendered by an ajax request initiated by another <h:form> beforehand. The rendered/updated <h:form> would then lose its view state. This is caused by a bug in the JavaScript API as described in JSF issue 790 which is already fixed for the shortly upcoming JSF 2.2.

In the meanwhile, with JSF 2.0/2.1, you need to explicltly specify the client ID of the <h:form> in the render (or for PrimeFaces, the update) attribute of the action in the other form.

E.g.

<h:commandButton ...>
   <f:ajax ... render=":listForm" />
</h:commandButton>

or

<p:commandButton ... update=":listForm" />

Or just make it a normal (non-ajax) request instead.

See also:

• Communication in JSF 2 - Ajax rendering of content which contains another form