Java Google云存储上载媒体链接空，但图像上载

Question

我试图上传图像到我的谷歌云存储中的现有桶。当我去检查的时候，图像文件被成功上传，但是返回的下载网址是null

private String uploadImage(File filePath, String blobName, File uploadCreds) throws FileNotFoundException, IOException{


   Storage storage = StorageOptions.newBuilder().setProjectId("myProjectId")
                .setCredentials(ServiceAccountCredentials.fromStream(new FileInputStream(uploadCreds)))
                .build()
                .getService();

                    String bucketName = "myBucketName"; 
                    Bucket bucket = storage.get(bucketName);
        BlobId blobId = BlobId.of(bucket.getName(), blobName);
        InputStream inputStream = new FileInputStream(filePath);
        BlobInfo blobInfo = BlobInfo.newBuilder(blobId).setContentType("image/jpeg").build();


    try (WriteChannel writer = storage.writer(blobInfo)) {
        byte[] buffer = new byte[1024];
        int limit;
        try {
            while ((limit = inputStream.read(buffer)) >= 0) {
                writer.write(ByteBuffer.wrap(buffer, 0, limit));
            }

        } catch (Exception ex) {
            ex.printStackTrace();
        }finally {
            writer.close();

        }
                     System.out.println("Image URL : " + blobInfo.getMediaLink());
                     System.out.println("Blob URL : " + blobInfo.getSelfLink());
                     return blobInfo.getMediaLink();
    }


}

FilePath是图像文件
BloName是一个随机图像名称
上传Creds是我的credintials.json文件

为什么blobInfo.getMediaLink（）和blobInfo.getSelfLink（）返回null<我做错了什么？




Answer 1

这是我的代码，它可以完美地工作

@RestController
@RequestMapping("/api")
public class CloudStorageHelper  {

    Credentials credentials = GoogleCredentials.fromStream(new FileInputStream("C:\\Users\\sachinthah\\Downloads\\MCQ project -1f959c1fc3a4.json"));
    Storage storage = StorageOptions.newBuilder().setCredentials(credentials).build().getService();

    public CloudStorageHelper() throws IOException {
    }

    @SuppressWarnings("deprecation")
    @RequestMapping(method = RequestMethod.POST, value = "/imageUpload112")
    public String uploadFile(@RequestParam("fileseee")MultipartFile fileStream)
            throws IOException, ServletException {
        BlobstoreService blobstoreService = BlobstoreServiceFactory.getBlobstoreService();
        String bucketName = "mcqimages";
        checkFileExtension(fileStream.getName());
        DateTimeFormatter dtf = DateTimeFormat.forPattern("-YYYY-MM-dd-HHmmssSSS");
        DateTime dt = DateTime.now(DateTimeZone.UTC);

        String fileName = fileStream.getOriginalFilename();

        BlobInfo blobInfo = BlobInfo.newBuilder(bucketName, fileName)
                .setAcl(new ArrayList<>(Arrays.asList(Acl.of(User.ofAllUsers(), Role.READER))))
                .build(),
        fileStream.getInputStream());

        System.out.println(blobInfo.getMediaLink());

        // sachintha added a comma after the link to identify the link that get generated
        return blobInfo.getMediaLink() + ",";
    }


private void checkFileExtension(String fileName) throws ServletException {
    if (fileName != null && !fileName.isEmpty() && fileName.contains(".")) {
        String[] allowedExt = {".jpg", ".jpeg", ".png", ".gif"};
        for (String ext : allowedExt) {
            if (fileName.endsWith(ext)) {
                return;
            }
        }
        throw new ServletException("file must be an image");
    }
}