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我有一个保存用户个人资料图片的实体。为了简单起见，我只存储服务 URL。我允许我的用户裁剪他们的图像。为此，我从服务 URL 获取图像并创建一个com.google.appengine.api.images.Image;此图像没有 blob 键，因为它是从字节数组创建的。将此图像存储为 blob 并获取服务 url 的最简单方法是什么？

URL url = new URL(currentProfile.getProfilePictureUrl());
InputStream input = url.openStream();
byte[] byteArray = IOUtils.toByteArray(input);
Image newImage = ImagesServiceFactory.makeImage(byteArray);

int imageWidth = newImage.getWidth();
int imageHeight = newImage.getHeight();

ImagesService imagesService = ImagesServiceFactory.getImagesService();
float lx = (float)x/(float)imageWidth;
float ty =  (float)y/(float)imageHeight;
float rx = (float)x2/(float)imageWidth;
float by = (float)y2/(float)imageHeight;
Transform resize = ImagesServiceFactory.makeCrop(lx, ty, rx, by);

Image transImage = imagesService.applyTransform(resize, newImage);

BlobstoreService blobStoreService = BlobstoreServiceFactory.getBlobstoreService();

//This doesn't work because transImage.getBlobKey() is null
ServingUrlOptions options =  ServingUrlOptions.Builder.withBlobKey(transImage.getBlobKey());
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1 回答 1

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您可以以编程方式将数据写入 blobstore。我使用这个小片段：

private BlobKey saveToBlobstore(String contentType, String imageName, byte[] imageData) throws IOException {
    // Get a file service
    FileService fileService = FileServiceFactory.getFileService();

    // Create a new Blob file and set the name to contain ref to UserImage
    AppEngineFile file = fileService.createNewBlobFile(contentType, imageName);

    // Open a channel to write to it
    FileWriteChannel writeChannel = fileService.openWriteChannel(file, true);

    writeChannel.write(ByteBuffer.wrap(imageData));
    writeChannel.closeFinally();

    // return the BlobKey
    return fileService.getBlobKey(file);
}
于 2013-01-25T07:04:49.720 回答