p：fileUpload总是返回null文件，并且永远不会调用Listener方法

Question

我遇到版本4.0的<p:fileUpload>问题，该文件永远不会在Bean中设置，并且永远不会调用监听器。我找到了许多解决方案，但它并没有解决我的问题 这是我的xhtml文件：

<h:form id="detailsDemandes" style="height:80%" enctype="multipart/form-data">



    <p:focus context="detailsDemandes" />



    <p:layout style="width:100%;height:80%;" id="layout">
        <p:layoutUnit position="#{positionBean.pos}" resizable="true"
            size="30%" style="height:100%">
            <p:dataTable id="cars" var="car"
                value="#{carController.beanList}" widgetVar="carsTable"
                filteredValue="#{dtColumnsView.filteredCars}"
                selectionMode="single" lazy="true"
                selection="#{carController.selected}"
                rowKey="#{not empty car.carId ? car.carId : car.hashCode() }">

                <p:ajax event="rowSelect"
                    update=":demandeForm :detailsDemandes :formButton"
                    listener="#{carController.onSelectCar}" />


                <p:ajax event="rowUnselect"
                    listener="#{carController.onUnselectCar}"
                    update=":demandeForm :detailsDemandes :formButton" />


                <p:columns value="#{carController.columns}" var="column"
                    columnIndexVar="colIndex" sortBy="#{car[column.property]}"
                    filterBy="#{car[column.property]}">
                    <f:facet name="header">
                        <h:outputText value="#{column.header}" />
                    </f:facet>
                    <h:outputText value="#{car[column.property]}" />
                </p:columns>
            </p:dataTable>
            <p:panelGrid style="width:70%;margin-left:4px">
            <p:row>
                <p:column styleClass="column" style="width:20%">
                    <p:fileUpload value="#{carController.file}" mode="advanced"
                        fileUploadListener="#{carController.fileUploadListener}">
                    </p:fileUpload>

                </p:column>


                <p:column styleClass="column" style="width:20%">
                    <p:graphicImage style="width:100px;" id="photo"
                        value="#{carController.image}">

                    </p:graphicImage>
                </p:column>
            </p:row>
            </p:panelGrid>




        </p:layoutUnit>
...
</p:layout>

我将此添加到我的web.XML：

<context-param>
  <param-name>primefaces.UPLOADER</param-name>
  <param-value>auto|native|commons</param-value>
</context-param>

<filter>
 <filter-name>PrimeFacesFileUploadFilter</filter-name>
 <filter-class>
  org.primefaces.webapp.filter.FileUploadFilter
 </filter-class>
</filter>
<filter-mapping>
 <filter-name>PrimeFacesFileUploadFilter</filter-name>
 <servlet-name>Faces Servlet</servlet-name>

</filter-mapping>

我在pom.xml中添加了这些依赖项：

<dependency>
        <groupId>org.apache.commons</groupId>
        <artifactId>commons-io</artifactId>
        <version>1.3.2</version>
    </dependency>
    <dependency>
        <groupId>commons-fileupload</groupId>
        <artifactId>commons-fileupload</artifactId>
        <version>1.2.2</version>
    </dependency>