我用的richfaces的fileupload组件不能激活fileUploadListener

public void listener(UploadEvent event) throws IOException{
        UploadItem item = event.getUploadItem();
         
        System.out.println("in listener");
    }<h:form>
        <h:panelGrid columns="2" columnClasses="top,top">
            <rich:fileUpload fileUploadListener="#{fileUploadBean.listener}"
                maxFilesQuantity="100"
                    immediateUpload="true"
                    autoclear="false"
                    addControlLabel="图片上传"
                    clearAllControlLabel="清除"
                    clearControlLabel=""
                    cancelEntryControlLabel="停止"
                    
                    style="height:100;"
                    acceptedTypes="jpg, gif, png, bmp">
                    <a4j:support event="onuploadcomplete" 
                        reRender="info"/>            </rich:fileUpload>
            <h:panelGroup id="info">
                <rich:panel bodyClass="info">
                    <f:facet name="header">
                        <h:outputText value="Uploaded Files Info" />
                    </f:facet>
                    <h:outputText value="No files currently uploaded"
                        rendered="#{fileUploadBean.size==0}" />
                    <rich:dataGrid columns="1" value="#{fileUploadBean.files}"
                        var="file" rowKeyVar="row">
                        <rich:panel>
                            <h:panelGrid columns="2">
                                <a4j:mediaOutput element="img" mimeType="image/jpeg"
                                    createContent="#{fileUploadBean.paint}" value="#{row}"
                                    style="width:100px; height:100px;" />
                                <h:panelGrid columns="2">
                                    <h:outputText value="File Name:" />
                                    <h:outputText value="#{file.name}" />
                                    <h:outputText value="File Length(bytes):" />
                                    <h:outputText value="#{file.length}" />
                                </h:panelGrid>
                            </h:panelGrid>
                        </rich:panel>
                    </rich:dataGrid>
                </rich:panel>
                <rich:spacer height="3"/>
                <br />
                <a4j:commandButton action="#{fileUploadBean.clearUploadData}"
                    reRender="info, upload" value="Clear Uploaded Data"
                    rendered="#{fileUploadBean.size>0}" />
            </h:panelGroup>
        </h:panelGrid>
    </h:form><?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="2.5" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee   http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
  <context-param>
    <param-name>javax.faces.CONFIG_FILES</param-name>
    <param-value>/WEB-INF/faces-config.xml</param-value>
  </context-param>
  <context-param>
        <param-name>org.richfaces.SKIN</param-name>
        <param-value>blueSky</param-value>
  </context-param>
  <filter> 
        <display-name>RichFaces Filter</display-name> 
        <filter-name>richfaces</filter-name> 
        <filter-class>org.ajax4jsf.Filter</filter-class> 
        <init-param>
           <param-name>createTempFiles</param-name>
           <param-value>true</param-value>
        </init-param>
        <init-param>
            <param-name>maxRequestSize</param-name>
            <param-value>20000000</param-value>
        </init-param>
    </filter> 
    <filter-mapping> 
        <filter-name>richfaces</filter-name> 
        <servlet-name>Faces Servlet</servlet-name>
        <dispatcher>REQUEST</dispatcher>
        <dispatcher>FORWARD</dispatcher>
        <dispatcher>INCLUDE</dispatcher>
    </filter-mapping>
  <servlet>
    <servlet-name>Faces Servlet</servlet-name>
    <servlet-class>javax.faces.webapp.FacesServlet</servlet-class>
    <load-on-startup>0</load-on-startup>
  </servlet>
  <servlet-mapping>
    <servlet-name>Faces Servlet</servlet-name>
    <url-pattern>*.jsf</url-pattern>
  </servlet-mapping>
  <welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
  </welcome-file-list>
</web-app>