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当我尝试使用 Java 模拟发布请求以上传到应用引擎 blobstore 时，出现以下异常：

WARNING: /_ah/login
java.lang.NullPointerException
  at com.google.appengine.api.users.dev.LoginCookieUtils.encodeEmailAsUserId(LoginCookieUtils.java:89)
  at com.google.appengine.api.users.dev.LoginCookieUtils.createCookie(LoginCookieUtils.java:41)
  at com.google.appengine.api.users.dev.LocalLoginServlet.doPost(LocalLoginServlet.java:90)

这是执行 POST 请求的代码：

byte[] htmlData = // ...I already have the byte array I want to store/update)

    BlobstoreService blobstoreService = BlobstoreServiceFactory.getBlobstoreService();
            String uploadURL = blobstoreService.createUploadUrl("/upload");

                         //add host if in dev mode
             if(uploadURL.indexOf("http") == -1)
             {
                 uploadURL = "http://localhost:8888" + uploadURL;
             }
             URL url = new URL(uploadURL);
             // create a boundary string
             String boundary = MultiPartFormOutputStream.createBoundary();
             URLConnection urlConn = MultiPartFormOutputStream.createConnection(url);
             urlConn.setReadTimeout(15000);
             urlConn.setRequestProperty("Accept", "*/*");
             urlConn.setRequestProperty("Content-Type", MultiPartFormOutputStream.getContentType(boundary));
             // set some other request headers...
             urlConn.setRequestProperty("Connection", "Keep-Alive");
             urlConn.setRequestProperty("Cache-Control", "no-cache");
             // no need to connect because getOutputStream() does it
             MultiPartFormOutputStream out = new MultiPartFormOutputStream(urlConn.getOutputStream(), boundary);
out.writeField("param", "value")
out.writeFile("myFile", "multipart/form-data", "content.html", htmlData);
         out.close();

然后在upload.java

public class Upload extends HttpServlet 
{

    private BlobstoreService blobstoreService = BlobstoreServiceFactory.getBlobstoreService();

    public void doPost(HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException 
    {
        UserService userService = UserServiceFactory.getUserService();
        User user = userService.getCurrentUser();
        Map<String, BlobKey> blobs = blobstoreService.getUploadedBlobs(req);
        BlobKey blobKey = blobs.get("myFile");
        String value = req.getParameter("param");
        Topic t = pm.getObjectById(Topic.class, key);
        t.setParam("value");
    try
    {
        pm.makePersistent(t);
    }

……

为什么我收到 encodeEmailAsUserId 异常？

PS writeFields 在数据存储区中保持并更新得很好，但我仍然得到这个异常。

4

1 回答 1

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我想出了解决方案。问题是我从中提取 MultiPartStream 代码的示例没有为身份验证 cookie 设置标头。

我只是将以下内容添加到我的中间人 servlet 中，它将 Post 数据传递给 Upload servlet。

    Cookie [] cookies = req.getCookies();
    String name = cookies[0].getName();
    String value = cookies[0].getValue();

...

 urlConn.setRequestProperty("Cookie", name + "=" + value);
于 2011-04-19T17:37:18.020 回答