在应用程序引擎中使用java下载blob

如何从app engine下载blob？？我想搜索一个特定的blob并提供一个下载链接。我尝试的是：

<input type="text" name="search"> 
<input type="submit" value="SEARCH" > 
<a href="/mygaeproject1">download link</a>

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你正朝着写的方向前进。请继续。但是当我使用链接时，你没有给出blob…怎么办？你需要将

blob键

传递给servlet，对吗？因此，链接应该是

href=“/mygaeproject1？blob key=xxxyyzzz”

所以现在我需要检索每个文件的每个blobkey值并传递t…对吗？您需要具有blobkey值才能下载它。

public class ProjectServlet extends HttpServlet {

  private BlobstoreService blobstoreService = BlobstoreServiceFactory.getBlobstoreService(); 

  public void doGet(HttpServletRequest req, HttpServletResponse resp) 
     throws IOException 
  {
    BlobKey blobKey = new BlobKey(req.getParameter("blob-key"));      
    blobstoreService.serve(blobKey, resp);
    BlobInfoFactory blobInfoFactory = new BlobInfoFactory();
    BlobInfo blobInfo = blobInfoFactory.loadBlobInfo(blobKey);
    resp.setContentLength(new Long(blobInfo.getSize()).intValue()); 
    resp.setHeader("content-type", blobInfo.getContentType()); 
    resp.setHeader("content-disposition", "attachment; filename=" + 
            blobInfo.getFilename()); 
    blobstoreService.serve(blobKey, resp); 
  }
}