为啥上传图片到 Blobstore 后回调失败？

Posted 2023-02-26

【中文标题】为啥上传图片到 Blobstore 后回调失败？

【英文标题】：Why does callback fail after uploading image to Blobstore?为什么上传图片到 Blobstore 后回调失败？

【发布时间】：2015-01-29 18:47:27

【问题描述】：

我正在尝试将照片上传到 blobstore。照片已成功上传到 blobstore，但我无法取回 blobkey 和 servingUrl。我尝试调试，发现没有对 BlobUpload.java 进行回调。它给出了一个错误“连接到 http://localhost:8888 被拒绝”我很困惑，因为 BlobUrlGet.java 调用没有问题并且照片已上传。我尝试了服务器和 servlet 的每种类型的 url，但它们都不起作用。

编辑： 我意识到如果我在调试模式（str 变量）中手动将“localhost:8888”更改为“10.0.2.2:8888”，“连接被拒绝”问题就会消失，但是这次它显示以下错误。

http://localhost:8888/_ah/upload/ahFteWZpcnN0YXBwZGVtbzEyM3IiCxIVX19CbG9iVXBsb2FkU2Vzc2lvbl9fGICAgICAgN4KDAError 405 HTTP 方法 POST 不受此 URL 支持

错误 405 HTTP 方法 POST 不受此 URL 支持

这是从 post 方法返回的。当我部署到 appengine 并从那里工作时，也是同样的错误。

我的代码如下。

BlobUrlGet.java

public class BlobUrlGet extends HttpServlet   
    BlobstoreService blServ = BlobstoreServiceFactory.getBlobstoreService();    
    public void doGet(HttpServletRequest req, HttpServletResponse resp)
            throws IOException   
        String blobUploadUrl = blServ.createUploadUrl("/blob");   
        resp.setStatus(HttpServletResponse.SC_OK);
        resp.setContentType("text/plain");    
        PrintWriter out = resp.getWriter();
        out.print(blobUploadUrl);
           

BlobUpload.java

public class BlobUpload extends HttpServlet 
    BlobstoreService blobstoreService = BlobstoreServiceFactory
            .getBlobstoreService();

    public void doPost(HttpServletRequest req, HttpServletResponse resp)
            throws IOException 
        try 
            List<BlobKey> blobs = blobstoreService.getUploads(req).get("file");
            BlobKey blobKey = blobs.get(0);

            ImagesService imagesService = ImagesServiceFactory
                    .getImagesService();
            ServingUrlOptions servingOptions = ServingUrlOptions.Builder
                    .withBlobKey(blobKey);

            String servingUrl = imagesService.getServingUrl(servingOptions);

            resp.setStatus(HttpServletResponse.SC_OK);
            resp.setContentType("application/json");

            JSONObject json = new JSONObject();

            json.put("servingUrl", servingUrl);
            json.put("blobKey", blobKey.getKeyString());

            PrintWriter out = resp.getWriter();
            out.print(json.toString());
            out.flush();
            out.close();
         catch (JSONException e) 

            e.printStackTrace();
        

    

安卓客户端

private class GetBlobUrlTask extends AsyncTask<Void, Void, Void> 

        @Override
        protected Void doInBackground(Void... arg0)  

        HttpClient httpClient = new DefaultHttpClient();    
        //This will invoke "ImgUpload servlet           
        HttpGet httpGet = new HttpGet("http://10.0.2.2:8888/bloburl"); 
        HttpResponse response;
        try 
            response = httpClient.execute(httpGet);         
            HttpEntity urlEntity = response.getEntity();
            InputStream in = urlEntity.getContent();
            String str = ""; 
            StringWriter writer = new StringWriter();
            String encoding = "UTF-8";
            IOUtils.copy(in, writer, encoding);
            str = writer.toString();
//              str = URLDecoder.decode(str, "UTF-8");
                HttpPost httppost = new HttpPost(str);
                File f = new File(picturePath);
                FileBody fileBody = new FileBody(f);
                MultipartEntityBuilder reqEntity = MultipartEntityBuilder.create();
                reqEntity.addPart("file", fileBody);
                reqEntity.addBinaryBody("Photo", f, ContentType.create("image/jpeg"), "foto2.jpg");
                httppost.setEntity(reqEntity.build());
                response = httpClient.execute(httppost); //Here "uploaded" servlet is automatically       invoked
                urlEntity = response.getEntity(); //Response will be returned by "uploaded" servlet in JSON format
                in = urlEntity.getContent();
                str = "";
                IOUtils.copy(in, writer, encoding);
                str = writer.toString();
                JSONObject resultJson = new JSONObject(str);
                blobKey = resultJson.getString("blobKey");
                servingUrl = resultJson.getString("servingUrl");    



         catch (ClientProtocolException e) 
            // TODO Auto-generated catch block
            e.printStackTrace();
         catch (IOException e) 
            // TODO Auto-generated catch block
            e.printStackTrace();
         catch (JSONException e) 
            // TODO Auto-generated catch block
            e.printStackTrace();
        

        return null;

web.xml

  <servlet>
    <servlet-name>BlobstoreURL</servlet-name>
    <servlet-class>com.google.samplesolutions.mobileassistant.BlobUrlGet</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>BlobstoreURL</servlet-name>
    <url-pattern>/bloburl</url-pattern>
  </servlet-mapping>

  <servlet>
    <servlet-name>BlobstoreUpload</servlet-name>
    <servlet-class>com.google.samplesolutions.mobileassistant.BlobUpload</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>BlobstoreUpload</servlet-name>
    <url-pattern>/blob</url-pattern>
  </servlet-mapping>

提前致谢。

【参考方案1】：

doPost 应该被覆盖。现在它完美地工作了。

public class BlobUpload extends HttpServlet 
    BlobstoreService blobstoreService = BlobstoreServiceFactory
            .getBlobstoreService();
    @Override
    public void doPost(HttpServletRequest req, HttpServletResponse resp)
            throws IOException 
        try 
            List<BlobKey> blobs = blobstoreService.getUploads(req).get("file");
            BlobKey blobKey = blobs.get(0);