Question

我尝试使用文件服务将数据存储在Google应用引擎中，然后我成功上传了它，但后来我注意到它没有存储为blob值。所以我用Google搜索并获得了谷歌提供的这个链接How do I handle multipart form data? or How do I handle file uploads to my app?。

在本文档中，代码如下所示，

 FileItemIterator iterator = upload.getItemIterator(req);
 while (iterator.hasNext()) {
 FileItemStream item = iterator.next();
 InputStream stream = item.openStream();
 if (item.isFormField()) {
 log.warning("Got a form field: " + item.getFieldName());
 } else {
 log.warning("Got an uploaded file: " + item.getFieldName() +", name = " + item.getName());

 // You now have the filename (item.getName() and the
 // contents (which you can read from stream). Here we just
 // print them back out to the servlet output stream, but you
 // will probably want to do something more interesting (for
 // example, wrap them in a Blob and commit them to the
 // datastore).

这里不了解如何将它们包装为blob并将它们提交到数据存储区。任何人都可以建议我如何解决这个问题。这种方式是否将文件存储为谷歌应用引擎中的blob值？

Answer 1

InputStream is = item.openStream();
try {
   FileService fileService = FileServiceFactory.getFileService();
   AppEngineFile file = fileService.createNewBlobFile(mime, fileName);
   boolean lock = true;
   FileWriteChannel writeChannel = fileService.openWriteChannel(file, lock);
   byte[] buffer = new byte[BUFFER_SIZE];
   int readBytes;
   while ((readBytes = is.read(buffer)) != -1) {
       writeChannel.write(ByteBuffer.wrap(buffer, 0, readBytes));
   }
   writeChannel.closeFinally();
   String blobKey = fileService.getBlobKey(file).getKeyString();
} catch (Exception e) {
   e.printStackTrace(resp.getWriter());
}

如何将文件包装为blob并将其作为数据存储区在google app engine java中提交

1 个答案: