Direct Get BlobStore Upload URL in GAE/J

구글 앱엔진 Java 에서 BlobStore 저장용 URL을 바로 받아 오기. 

public void doGet(HttpServletRequest req, HttpServletResponse res) throws IOException
{
    final String url = blobstoreService.createUploadUrl("/upload");

    final PrintWriter printWirter = res.getWriter();

    res.setContentType("text/plain");
    printWirter.write(url);

}