使用icefaces在liferay portlet中上传和显示图像

Question

我有这个XHTML代码：

<h:form>
<ice:graphicImage value="#{uploadImage.byteArrayImage}" 
                  rendered="#{uploadImage.byteArrayImage!=null}"/>
<ace:fileEntry id="fileEntryComp" 
               label="File Entry" 
               relativePath="uploaded"
               useOriginalFilename="true" 
               fileEntryListener="#{uploadImage.customValidator}"/> 
<h:commandButton value="Upload Image" / >
<h:message for="fileEntryComp" />
</h:form>

这个用于上传图片的java方法：

    public void customValidator(FileEntryEvent entryEvent) throws IOException {    
        FileEntryResults results = ((FileEntry) entryEvent.getComponent()).getResults();
        for (FileEntryResults.FileInfo file : results.getFiles()) {
            if (file.isSaved()) {
                if (!file.getContentType().equals("image/png")) {
                    file.updateStatus(new FileEntryStatus() {    
                        @Override
                        public boolean isSuccess() {
                            return false;
                        }    
                        @Override
                        public FacesMessage getFacesMessage(
                                FacesContext facesContext, UIComponent fileEntry, FileEntryResults.FileInfo fi) {
                            return new FacesMessage(FacesMessage.SEVERITY_ERROR,
                                    "Only PNG files can be uploaded. Your upload has been cancelled.",
                                    "Only PNG files can be uploaded. Your upload has been cancelled.");
                        }
                    },
                            true, true);
                } else {            
                    this.byteArrayImage = readIntoByteArray(new FileInputStream(file.getFile()));                       
                }
            }
        }
    }    

我需要在页面上上传和显示图片，但它确实有用，我不知道为什么。谢谢你的回答。