当我将图像存储在Google驱动器上时，如何在项目中显示缩略图

Question

我正在成功上传文件并将其存储在Google驱动器上。 现在我只想获取文档的缩略图以显示在下载链接的位置。 请建议我怎么办？ 这是我用于上传文档的控制器代码。

'`@RequestMapping(value = "/upload", method = RequestMethod.POST)
public ModelAndView uploadFile(@RequestParam(value = "ddid", required = true) Integer ddid,
        @RequestParam(value = "catageryId", required = true) Integer catageryId,
        @RequestParam(value = "document", required = true) GMultipartFile document[], HttpServletRequest request, HttpServletResponse resp) {

    DdeDriveDocuments ddeDriveDocuments = new DdeDriveDocuments();
    if (ServletFileUpload.isMultipartContent(request) && document != null) {
        for (GMultipartFile gdocument : document) {
            try {
                boolean user = true;
                List<DdeDriveDocuments> dds = ddeDriveDocumentsService.fatchData(ddid, catageryId);
                for (DdeDriveDocuments file : dds) {
                    System.out.println(file.getDocument_name());
                    if (file.getDocument_name().equals(gdocument.getOriginalFilename())) {
                        user = false;
                    }
                }

                if (user == true) {
                    ddeDriveDocuments
                            .setDocument_name((gdocument.getName() != null ? gdocument.getOriginalFilename() : ""));
                    System.out.println(gdocument.getOriginalFilename());
                    ddeDriveDocuments.setDocument_created(new Date());
                    ddeDriveDocuments.setCatagery_id(catageryId);
                    ddeDriveDocuments.setDd_id(ddid);
                    ddeDriveDocuments.setDd_uuid(GeneralUtil.getUUID());

                    Lawyer googleAuthToken = lawyerService
                            .getAuthorisedUserToken(Configurator.getInstance().getDriveAccountEmail());
                    if (googleAuthToken != null) {
                        // upload file in drive
                        if (ServletFileUpload.isMultipartContent(request) && document != null) {

                            // It's value either we need to get from form.
                            String description = "Testing";

                            File file = DriveService.uploadDocumentToDrive(googleAuthToken, gdocument,
                                    ddeDriveDocuments.getDocument_name(), description);



                                File thumFile = DriveService.getFileById(googleAuthToken, file.getId());

                                System.out.println("thab url"+thumFile.getThumbnail());

                            System.out.println(file.getThumbnailLink());



                            if (file != null) {
                                ddeDriveDocuments.setDocument_drive_id(file.getId());
                                ddeDriveDocuments.setThumburl(thumFile.getThumbnailLink());
                                ddeDriveDocuments = ddeDriveDocumentsService.create(ddeDriveDocuments);
                            }
                        }
                    } else {
                        System.out.println("Autorised token not available for configured drive account.");
                    }

                }

                else {
                    System.out.println("wroung Input");
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }

    return new ModelAndView("redirect:/al/lawyer/ddfiles/" + ddid + "/" + catageryId);
}`'

Answer 1

您必须使用Drive REST API方法文件：get 。 该方法的结果包含thumbnailLink，但是根据文档，它是“到文件缩略图的短暂链接。 通常持续几个小时。”

另外，如果您只想显示漂亮的内容，则可以获取文件的内容类型或扩展名，并为该类型的所有文件显示通用缩略图。 我建议这样做是因为根据我的经验，驱动器api并不是响应速度很快的api之一。

另外，您可以/应该在应用程序中缓存缩略图，以减少驱动器api请求的数量，从而提高页面性能。