使用JSF 2.2的Google App Engine中的文件上传错误

Question

我正在使用Eclipse Kepler在Google App Engine项目（api-1.0-sdk-1.8.4）中使用Mojarra 2.2.0和tomahawk12-1.1.14（t：inputFileUpload）。

从Eclipse本地运行时，该项目可以完美运行，但是如果尝试上传文件时将其部署到Google App Engine，则会收到以下错误消息：

/faces/tmotifs.xhtml
java.lang.NullPointerException
    at java.io.File.<init>(File.java:290)
    at org.apache.myfaces.webapp.filter.MultipartRequestWrapper.parseRequest(MultipartRequestWrapper.java:141)
    at org.apache.myfaces.webapp.filter.MultipartRequestWrapper.getParameter(MultipartRequestWrapper.java:299)
    at com.sun.faces.context.RequestParameterMap.get(RequestParameterMap.java:75)
    at com.sun.faces.context.RequestParameterMap.get(RequestParameterMap.java:56)
    at java.util.Collections$UnmodifiableMap.get(Collections.java:1339)
    ...

我在tmotifs.xhtml中使用文件上传组件，如下所示：

<h:form enctype="multipart/form-data">
    <t:inputFileUpload value="#{trainingBean.uploadedFile}"
        accept="text/x-fasta" requiredMessage="A fasta file must be selected" />
    <h:commandButton value="Refresh" actionListener="#{trainingBean.upload}" />
....

支持bean如下所示：

@ManagedBean
@SessionScoped
public class TrainingBean implements Serializable {
    private static final long serialVersionUID = 1L;
    private UploadedFile uploadedFile;

    public UploadedFile getUploadedFile() {
        return uploadedFile;
    }

    public void setUploadedFile(UploadedFile uploadedFile) {
        this.uploadedFile = uploadedFile;
    }

    public void upload() {
        if( uploadedFile == null ) {
            refresh();
            return;
        }

        this.inputList.clear();
        try {
            Reader rd = new InputStreamReader(uploadedFile.getInputStream());
            inputGroupList = InputGroup.readEntries(rd); 
            rd.close();
            for( InputGroup p : inputGroupList )
                this.inputList.addAll(p.getMotifs());
            uploadError = null;
            inputFileName = uploadedFile.getName();
        } catch (IOException e) {
            uploadError = e.getMessage();
            e.printStackTrace();
        } catch( InvalidSequenceException e ) {
            uploadError = e.getMessage();
            e.printStackTrace();
        }

        refresh();
    }
...

和web.xml：

<?xml version="1.0" encoding="utf-8" standalone="no"?>
<web-app
    xmlns="http://java.sun.com/xml/ns/javaee"
    xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
    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">
<display-name>JavaServerFaces</display-name>    

    <context-param>
        <param-name>javax.faces.STATE_SAVING_METHOD</param-name>
        <!--<param-value>client</param-value>-->
        <param-value>server</param-value>
    </context-param>
    <context-param>
        <param-name>javax.faces.DEFAULT_SUFFIX</param-name>
        <param-value>.xhtml</param-value>
    </context-param>
    <context-param>  
        <param-name>com.sun.faces.expressionFactory</param-name>  
        <param-value>com.sun.el.ExpressionFactoryImpl</param-value>  
    </context-param>
    <!-- Disable use of threading for single-threaded environments such as the Google AppEngine. -->
    <context-param>
        <param-name>com.sun.faces.enableThreading</param-name>
        <param-value>false</param-value>
    </context-param>    
    <!-- Change to "Production" when you are ready to deploy -->
    <context-param>
        <param-name>javax.faces.PROJECT_STAGE</param-name>
        <param-value>Development</param-value>
    </context-param>
    <context-param>
        <param-name>javax.faces.FACELETS_SKIP_COMMENTS</param-name>
        <param-value>true</param-value>
    </context-param>

    <!-- ***** Specify session timeout of thirty (30) minutes. ***** -->
    <session-config>
        <session-timeout>30</session-timeout>
    </session-config>

    <!-- Welcome page -->
    <welcome-file-list>
        <welcome-file>faces/home.xhtml</welcome-file>
    </welcome-file-list>

    <!-- JSF mapping -->
    <servlet>
        <servlet-name>Faces Servlet</servlet-name>
        <servlet-class>javax.faces.webapp.FacesServlet</servlet-class>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>Faces Servlet</servlet-name>
        <url-pattern>/faces/*</url-pattern>
        <url-pattern>*.jsf</url-pattern>
        <url-pattern>*.xhtml</url-pattern>
    </servlet-mapping>

    <!-- MyFaces Tomahawk -->
    <filter>
        <filter-name>MyFacesExtensionsFilter</filter-name>
        <filter-class>org.apache.myfaces.webapp.filter.ExtensionsFilter</filter-class>
        <init-param>
            <param-name>uploadMaxFileSize</param-name>
            <param-value>20m</param-value>
        </init-param>
    </filter>
    <filter-mapping>
        <filter-name>MyFacesExtensionsFilter</filter-name>
        <servlet-name>Faces Servlet</servlet-name>
    </filter-mapping>
    <filter-mapping>
        <filter-name>MyFacesExtensionsFilter</filter-name>
        <url-pattern>/faces/myFacesExtensionResource/*</url-pattern>
    </filter-mapping>

    <error-page>
        <exception-type>javax.faces.application.ViewExpiredException</exception-type>
        <location>/faces/home.xhtml</location>
    </error-page>

    <!-- System -->
    <servlet>
        <servlet-name>SystemServiceServlet</servlet-name>
        <servlet-class>com.google.api.server.spi.SystemServiceServlet</servlet-class>
        <init-param>
            <param-name>services</param-name>
            <param-value/>
        </init-param>
    </servlet>  
    <servlet-mapping>
        <servlet-name>SystemServiceServlet</servlet-name>
        <url-pattern>/_ah/spi/*</url-pattern>
    </servlet-mapping>

    <listener>
        <listener-class>es.ehu.grk.wregex.gae.ServletListener</listener-class>
    </listener>
</web-app>

所以我的问题是，我缺少什么吗？ 为什么t：inputFileUpload在本地GAE服务器上运行时可以正常运行，而在部署时却不能正常运行？

任何帮助/方向都很好。 先感谢您！

Answer 1

最后，我按照GAE上有关JSF文件上传的说明，通过在高级模式下使用PrimeFaces中的fileUpload（简单文件上传不起作用）解决了该问题，但不是在后备bean中使用BlobUtils（现已弃用？），而是从备份bean中读取文件记忆为：

public void uploadedFileEvent(FileUploadEvent event) {
    Reader rd = new InputStreamReader(new ByteArrayInputStream(event.getFile().getContents()));
    //...
}