Using on a List doesn't update

问题:

Here is the scenario (simplified):

There is a bean (call it mrBean) with a member and the appropriate getters/setters:

private List<String> rootContext;

public void addContextItem() {
    rootContext.add(\"\");
}

The JSF code:

<h:form id=\"a_form\">
            <ui:repeat value=\"#{mrBean.stringList}\" var=\"stringItem\">
                    <h:inputText value=\"#{stringItem}\" />
            </ui:repeat>
            <h:commandButton value=\"Add\" action=\"#{mrBean.addContextItem}\">
                <f:ajax render=\"@form\" execute=\"@form\"></f:ajax>
            </h:commandButton>
</h:form>

The problem is, when clicking the \"Add\" button, the values that were entered in the <h:inputText/> that represent the Strings in the stringList aren\'t executed.

Actually, the mrBean.stringList setter (setStringList(List<String> stringList)) is never called.

Any idea why?

Some info - I\'m using MyFaces JSF 2.0 on Tomcat 6.

回答1:

The String class is immutable and doesn\'t have a setter for the value. The getter is basically the Object#toString() method.

You need to get/set the value directly on the List instead. You can do that by the list index which is available by <ui:repeat varStatus>.

<ui:repeat value=\"#{mrBean.stringList}\" varStatus=\"loop\">
    <h:inputText value=\"#{mrBean.stringList[loop.index]}\" />
</ui:repeat>

You don\'t need a setter for the stringList either. EL will get the item by List#get(index) and set the item by List#add(index,item).