file-upload - Primefaces Multiple FileUpload 不显示文件也不触发handleFileUpload

Question

我从一周开始就在搜索，但找不到适合我的问题的解决方案。所以我在这里问专家。

我正在尝试使用 FileUpload 实现一个页面来上传并在同一页面上上传后显示图像。

我的问题是，如果我将 ManagedBean 设置为@RequestScope，handleFileUpload则不会触发该功能。如果我将其设置为@ViewScope，该功能将被触发，但错误“流式动态资源中的错误”。显示。

这是我的文件：

1. web.xml

   <filter>
   <filter-name>PrimeFaces FileUpload Filter</filter-name>
   <filter-class>org.primefaces.webapp.filter.FileUploadFilter</filter-class>
   <init-param>
       <param-name>thresholdSize</param-name>
       <param-value>2097152</param-value>
   </init-param>
   <init-param>
       <param-name>uploadDirectory</param-name>
       <param-value>E:/uploadedImages</param-value>
   </init-param>
   

   PrimeFaces FileUpload Filter Faces Servlet

2. 豆

   @ManagedBean
   @RequestScoped
   public class ImageManager implements Serializable {
   
   private final static int MAX_UPLOADED_FILES = 5;
   private final static String UPLOADED_FILES_PATH = "E:/uploadedImages";
   
   private final Map<UUID, UploadedFile> uploadedFiles = new HashMap<>();
   
   public List<String> getListImages() {
       final List<String> result = new ArrayList<>();
   
       for (final UUID uuid : uploadedFiles.keySet())
           result.add(uuid.toString());
   
       return result;
   }
   
   public StreamedContent getImage() {
       final ExternalContext externalContext = FacesContext.getCurrentInstance().getExternalContext();
       final String imageId = (String) externalContext.getRequestMap().get("imageId");
   
       if (imageId != null) {
           final UUID imageIndex = UUID.fromString(imageId);
           return new DefaultStreamedContent(new ByteArrayInputStream(uploadedFiles.get(imageIndex).getContents()), "image/jpg");
       }
   
       return null;
   }
   
   public void handleFileUpload(FileUploadEvent event) {
       if (uploadedFiles.size() < MAX_UPLOADED_FILES) {
           final UploadedFile uploadedFile = event.getFile();
           if (uploadedFile != null) {
               uploadedFiles.put(UUID.randomUUID(), uploadedFile);
           }
       }
   }
   
   }
   

3. xhtml

                 <p:fileUpload fileUploadListener="#{imageManager.handleFileUpload}"  
                           mode="advanced"
                           multiple="true"  
                           sizeLimit="2097152"
                           allowTypes="/(\.|\/)(gif|jpe?g|png)$/"
                           uploadLabel="Hochladen"
                           auto="false"
                           cancelLabel="Abbrechen"
                           invalidFileMessage="Die ausgewählte Datei ist kein zugelassene Bilddatei"
                           invalidSizeMessage="Die maximale Bildgröße ist 2MB"
                           label="Datei Auswählen"
                           update="imageList"
                           />
   
   
   
       <ui:repeat value="#{imageManager.listImages}" var="imageId" id="imageList">
           <h:outputText value="#{imageId}" />
           <p:graphicImage value="#{imageManager.image}">
               <f:param id="imageId" name="imageId" value="#{imageId}" />
           </p:graphicImage>
       </ui:repeat>  
   

Answer 1

@Daniel，相信我。在我在这里发布我的问题之前，我已经搜索了很多天。但我已经自己解决了这个问题。

如果有人遇到同样的问题，这里是解决方案：

    @Controller
    @Scope(WebApplicationContext.SCOPE_REQUEST)
    public class ImageManager implements Serializable {

        private final static int MAX_UPLOADED_FILES = 5;
        private final static String UPLOADED_FILES_PATH = "E:/uploadedImages";

        private final static Map<UUID, UploadedFile> uploadedFiles = new HashMap<>();

        private final static List<String> listImages = new ArrayList<>();
        private StreamedContent image;

        private static StreamedContent defaultImage = null;
        static {
            try {
                defaultImage = new DefaultStreamedContent(new FileInputStream(new File("E:\\uploadedImages\\t.jpg")), "image/jpg");
            }
            catch (FileNotFoundException e) {
                e.printStackTrace();
            }        
        }

        public List<String> getListImages() {
            return listImages;
        }

        public StreamedContent getImage() {
            final ExternalContext externalContext = FacesContext.getCurrentInstance().getExternalContext();
            final String imageId = (String) externalContext.getRequestParameterMap().get("imageId");

            if (imageId != null) {
                final UUID imageIndex = UUID.fromString(imageId);
                image = new DefaultStreamedContent(new ByteArrayInputStream(uploadedFiles.get(imageIndex).getContents()), "image/jpg");

                return image;
            }

            return defaultImage;
        }

        public void handleFileUpload(FileUploadEvent event) {
            if (uploadedFiles.size() < MAX_UPLOADED_FILES) {
                final UploadedFile uploadedFile = event.getFile();
                if (uploadedFile != null) {
                    final UUID uuid = UUID.randomUUID();
                    uploadedFiles.put(uuid, uploadedFile);
                    listImages.add(uuid.toString());
                }
            }
        }

        public void setImage(StreamedContent image) {
            this.image = image;
        }

    }