Jsf 如何获取PrimeFaces DefaultMenuItem的子级

我尝试在bean中构建菜单模型，并将其与标记p:menubar绑定

<p:menubar class="menu" model="#{layoutView.menuModel}" /> 

我得到一个空指针异常。我查了一个源代码

 org.primefaces.model.menu.DefaultMenuItem

和方法getChildren返回null

我想知道如何将panelGrid放入p:menuitem

我也试过切换

 DefaultMenuItem into UIMenuItem 

但是通过创建菜单模型，我得到了以下错误

  java.lang.IllegalArgumentException: 1
        at javax.faces.component.UIComponentBase.validateId(UIComponentBase.java:586)
        at javax.faces.component.UIComponentBase.setId(UIComponentBase.java:412)
        at org.primefaces.model.menu.BaseMenuModel.generateUniqueIds(BaseMenuModel.java:56)
        at org.primefaces.model.menu.BaseMenuModel.generateUniqueIds(BaseMenuModel.java:44)
        at org.primefaces.model.menu.DefaultMenuModel.generateUniqueIds(DefaultMenuModel.java:28)
        at org.primefaces.component.menu.BaseMenuRenderer.encodeEnd(BaseMenuRenderer.java:111)
        at javax.faces.component.UIComponentBase.encodeEnd(UIComponentBase.java:919)
        at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1863)
        at javax.faces.render.Renderer.encodeChildren(Renderer.java:176)
        at javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:889)
        at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1856)
        at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1859)

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有人能帮我解决这个问题吗？如果有人能帮我，我将不胜感激。

为什么不扩展该类并重写该方法？或者甚至通过在您自己的项目中添加一个带有更改代码的类来“重写整个类”？为什么不扩展该类并重写该方法？或者甚至通过在您自己的项目中添加一个带有更改代码的类来“覆盖整个类”？

 DefaultMenuItem into UIMenuItem 

  java.lang.IllegalArgumentException: 1
        at javax.faces.component.UIComponentBase.validateId(UIComponentBase.java:586)
        at javax.faces.component.UIComponentBase.setId(UIComponentBase.java:412)
        at org.primefaces.model.menu.BaseMenuModel.generateUniqueIds(BaseMenuModel.java:56)
        at org.primefaces.model.menu.BaseMenuModel.generateUniqueIds(BaseMenuModel.java:44)
        at org.primefaces.model.menu.DefaultMenuModel.generateUniqueIds(DefaultMenuModel.java:28)
        at org.primefaces.component.menu.BaseMenuRenderer.encodeEnd(BaseMenuRenderer.java:111)
        at javax.faces.component.UIComponentBase.encodeEnd(UIComponentBase.java:919)
        at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1863)
        at javax.faces.render.Renderer.encodeChildren(Renderer.java:176)
        at javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:889)
        at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1856)
        at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1859)