javax.faces.FacesException：目标模型Type不是Collection或Array

Question

提交JSF表单时，我收到以下异常：

Caused by: javax.faces.FacesException: Target model Type is no a Collection or Array 
    at com.sun.faces.renderkit.html_basic.MenuRenderer.convertSelectManyValuesForModel(MenuRenderer.java:388) [:2.0.3-] 
    at com.sun.faces.renderkit.html_basic.MenuRenderer.convertSelectManyValue(MenuRenderer.java:125) [:2.0.3-] 
    at com.sun.faces.renderkit.html_basic.MenuRenderer.getConvertedValue(MenuRenderer.java:311) [:2.0.3-] 
    at javax.faces.component.UIInput.getConvertedValue(UIInput.java:1023) [:2.0.3-]     at javax.faces.component.UIInput.validate(UIInput.java:953) [:2.0.3-] 
    at javax.faces.component.UIInput.executeValidate(UIInput.java:1204) [:2.0.3-] 
    at javax.faces.component.UIInput.processValidators(UIInput.java:693) [:2.0.3-] 
    at javax.faces.component.UIComponentBase.processValidators(UIComponentBase.java:1081) [:2.0.3-] 
    at javax.faces.component.UIComponentBase.processValidators(UIComponentBase.java:1081) [:2.0.3-] 
    at javax.faces.component.UIComponentBase.processValidators(UIComponentBase.java:1081) [:2.0.3-] 
    at javax.faces.component.UIComponentBase.processValidators(UIComponentBase.java:1081) [:2.0.3-] 
    at javax.faces.component.UIComponentBase.processValidators(UIComponentBase.java:1081) [:2.0.3-] 
    at javax.faces.component.UIForm.processValidators(UIForm.java:240) [:2.0.3-] 
    at org.ajax4jsf.component.AjaxViewRoot$3.invokeContextCallback(AjaxViewRoot.java:439) [:3.3.1.GA] 
    at org.ajax4jsf.component.AjaxViewRoot.processPhase(AjaxViewRoot.java:238) [:3.3.1.GA] 
    at org.ajax4jsf.component.AjaxViewRoot.processValidators(AjaxViewRoot.java:455) [:3.3.1.GA] 
    at com.sun.faces.lifecycle.ProcessValidationsPhase.execute(ProcessValidationsPhase.java:72) [:2.0.3-]   at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:97) [:2.0.3-] 
    at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:114) [:2.0.3-] 
    at javax.faces.webapp.FacesServlet.service(FacesServlet.java:308) [:2.0.3-]
    ... 42 more

这是怎么造成的，我该如何解决？

Answer 1

javax.faces.FacesException: Target model Type is no a Collection or Array
    at com.sun.faces.renderkit.html_basic.MenuRenderer.convertSelectManyValuesForModel(MenuRenderer.java:388)

此异常表示您在视图中有一个UISelectMany组件，例如<h:selectManyMenu>或<h:selectManyListbox>，其值未绑定到集合或数组。这个不对。它的值必须绑定到一个集合（如List<Entity>）或数组（如Entity[]），因为该组件可以检索多个提交的值。

假设您正在使用<h:selectManyMenu>类型的项目，这是一个正确的String如何看起来的启动示例：

<h:selectManyMenu value="#{bean.selectedItems}">
    <f:selectItems value="#{bean.availableItems}" />
</h:selectManyMenu>
<h:commandButton value="submit" action="#{bean.submit}" />

同

private List<String> selectedItems; // Note: List<String> and thus NOT String!
private List<String> availableItems;

@PostConstruct
public void init() {
    availableItems = Arrays.asList("one", "two", "three", "four", "five");
}

public void submit() {
    System.out.println("Selected items: " + selectedItems);
}

See also:

• How to get all the selected values from h:selectManyListbox in the backend bean in case of JSF?

Answer 2

我的解决方案是：我从process标签的标签<p:commandButton>中删除了属性“dtSubItem”，并且一切正常。命令按钮是在提交事件上提交数据表。

处理了第一个请求，但是在第二个错误出现时，填充了数据表。

<div class="ui-g-12 ui-md-6 ui-lg-2">
  <div class="espacoCampo">
      <p:outputLabel value=""  />  
          <p:commandButton  actionListener="#{managedBean.adicionarSubItemPanel(item)}"
                update="dtSubItem"
                title="Clique aqui para adicionar SubItem"
                icon="fa fa-plus"
                value="Adicionar"
                process="@this dtSubItem cadSubItens"
                iconPos="right"
                 >
      </p:commandButton>
    </div>
</div>


<p:dataTable var="subItem" id="dtSubItem" emptyMessage="Sem registros adicionados" value="#{item.btpResolucaoItemSubitemList}">
...
</p:dataTable>