JSF2-f:ajax元素的作用域是什么?

回答点2:

<h:inputText styleClass="id_tag" value="#{entryRecorder.tag}"
    valueChangeListener="#{entryRecorder.tagUpdated}">
    <f:ajax render="category" event="blur" />
</h:inputText>

豆子:

@ManagedBean
@ViewScoped
public class EntryRecorder {
    private String tag;
    private String category;
    @EJB
    private ExpenseService expenseService;

    public void tagUpdated(ValueChangeEvent e) {
        String value = (String) e.getNewValue();
        setCategory(expenseService.getCategory(value));
    }
}

xhtml格式:

<h:form>
    <h:outputText value="Tag:" />
    <h:inputText value="#{entryRecorder.tag}">
        <f:ajax render="category" event="valueChange"/>
    </h:inputText>
    <h:outputText value="Category:" />
    <h:inputText value="#{entryRecorder.category}" id="category" />
</h:form>

豆子:

@ManagedBean
@RequestScoped
public class EntryRecorder {
    private String tag;
    private String category;

    public String getCategory() {
        return category;
    }

    public String getTag() {
        return tag;
    }

    public void setCategory(String category) {
        this.category = category;
    }

    public void setTag(String tag) {
        this.tag = tag;
        tagUpdated();
    }

    private void tagUpdated() {
        category = tag;
    }
}