0

嗨，我是谷歌应用引擎的新手。我通过本教程

我成功地运行了这些示例项目。在此我必须上传一个文件，然后它返回相同的文件。但是我使用这个 url 给出了一个 url，我必须将一个文件上传到 blobstore。然后再次下载它。任何人都可以帮助如何通过网址上传文件。这是 index.jsp 文件的代码

<%@ page import="com.google.appengine.api.blobstore.BlobstoreServiceFactory" %>
<%@ page import="com.google.appengine.api.blobstore.BlobstoreService" %>

<%
    BlobstoreService blobstoreService = BlobstoreServiceFactory.getBlobstoreService();
%>


<html>
    <head>
        <title>Upload Test</title>
    </head>
    <body>
        <form action="<%= blobstoreService.createUploadUrl("/upload") %>" method="post" enctype="multipart/form-data">
            <input type="text" name="foo">
            <input type="file" name="myFile">
            <input type="submit" value="Submit">
        </form>
    </body>
</html>

这是serve.java代码

package org.ritesh;
import java.io.IOException;

import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.google.appengine.api.blobstore.BlobKey;
import com.google.appengine.api.blobstore.BlobstoreService;
import com.google.appengine.api.blobstore.BlobstoreServiceFactory;

public class Serve extends HttpServlet {
    private BlobstoreService blobstoreService = BlobstoreServiceFactory.getBlobstoreService();

public void doGet(HttpServletRequest req, HttpServletResponse res)
    throws IOException {
        BlobKey blobKey = new BlobKey(req.getParameter("blob-key"));
        blobstoreService.serve(blobKey, res);
    }
}

UploadServlet 代码在这里

package org.ritesh;

import java.io.IOException;
import java.util.Map;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.google.appengine.api.blobstore.BlobKey;
import com.google.appengine.api.blobstore.BlobstoreService;
import com.google.appengine.api.blobstore.BlobstoreServiceFactory;

public class UploadServlet extends HttpServlet {

    private BlobstoreService blobstoreService = BlobstoreServiceFactory.getBlobstoreService();


    public void doPost(HttpServletRequest req, HttpServletResponse res)
        throws ServletException, IOException {

        Map<String, BlobKey> blobs = blobstoreService.getUploadedBlobs(req);
        BlobKey blobKey = blobs.get("myFile");

        if (blobKey == null) {
            res.sendRedirect("/");
        } else {
            res.sendRedirect("/serve?blob-key=" + blobKey.getKeyString());
        }
    }
}

它运行良好，请建议任何修改，以便通过 url 上传文件

4

1 回答 1

0

如果您希望用户将文件发布到您自己的 URL，那么您需要使用Files API来写入 blobstore。

但是，如果可以的话，使用您已经在处理上传的方法可能会更好。它允许上传更大的文件，并且很可能更有效，因为上传是由 Google 基础架构而不是您的应用程序实例处理的。

于 2012-08-11T00:51:17.820 回答