将图像从Android客户端发送到AppEngine Cloud Endpoint

我正在使用AppEngine后端开发Android应用程序。 我正在使用Java中的Google Cloud Endpoints创建服务器部分。 我的问题是我无法从客户端向服务器发送位图。

我使用了这个问题的答案，但即使客户端部分似乎没有任何问题，服务器部分也根本不接收数据。 我也认为这个解决方案可能有点复杂，它可能会以不同的，更简单的方式工作，但这是我第一次实现服务器并第一次向它发送图片，所以我接受任何有关此的好建议。 谢谢！

这是我的代码：

String boundary = Long.toHexString(System.currentTimeMillis()); // Just generate some unique random value. String CRLF = "\r\n"; // Line separator required by multipart/form-data. String charset = "UTF-8"; HttpURLConnection connection = (HttpURLConnection) new URL("https://path_to_my_app/_ah/api/registration/v1/uploadImage").openConnection(); connection.setDoOutput(true); connection.setReadTimeout(60000); connection.setRequestMethod("POST"); connection.setRequestProperty("Content-Type", "multipart/form-data; boundary=" + boundary); PrintWriter writer = null; try { OutputStream output = connection.getOutputStream(); writer = new PrintWriter(new OutputStreamWriter(output, charset), true); // true = autoFlush, important! // Send text file. writer.append("--" + boundary).append(CRLF); writer.append("Content-Disposition: form-data; name=\"textFile\"; filename=\"" + somename + "\"").append(CRLF); writer.append("Content-Type: text/plain; charset=" + charset).append(CRLF); writer.append(CRLF).flush(); BufferedReader reader = null; ByteArrayOutputStream outputStream = new ByteArrayOutputStream(); photo.compress(Bitmap.CompressFormat.PNG, 100, outputStream); byteArray = stream.toByteArray(); try { reader = new BufferedReader(new InputStreamReader(new ByteArrayInputStream(byteArray), charset)); for (String line; (line = reader.readLine()) != null;) { writer.append(line).append(CRLF); } } finally { if (reader != null) try { reader.close(); } catch (IOException logOrIgnore) {} } writer.flush(); // End of multipart/form-data. writer.append("--" + boundary + "--").append(CRLF); } finally { if (writer != null) { writer.close(); } } 

服务器部分：

 @ApiMethod(name = "uploadImage", httpMethod = "POST") public void uploadImage(HttpServletRequest request, HttpServletResponse response) throws IOException { ServletFileUpload fileUpload = new ServletFileUpload(); try { FileItemIterator iterator = fileUpload.getItemIterator(request); while(iterator.hasNext()){ FileItemStream itemStream = iterator.next(); String fieldName = itemStream.getFieldName(); log.info("field name:"+fieldName); InputStream stream = itemStream.openStream(); String result = getStringFromInputStream(stream); log.info("result: "+result); stream.close(); } } catch (FileUploadException e) { e.printStackTrace(); } 

}

我现在得到204没有内容类型。

Answer 1

我做的！

我认为这不是最好的方法，但它正在工作，所以我很好，直到我得到一个更好的解决方案。

所以我采用Bitmap图像并将其转换为String：

 ByteArrayOutputStream outputStream = new ByteArrayOutputStream(); bitmap.compress(Bitmap.CompressFormat.PNG, 100, outputStream); byte[] bitmapByte = outputStream.toByteArray(); String stringEncodedImage = Base64.encodeToString(bitmapByte, Base64.DEFAULT); 

然后我创建一个httpPostRequest并为其设置一个JsonObject，并将图像转换为String。

 HttpClient httpClient = new DefaultHttpClient(); HttpPost httpPost = new HttpPost("https://my_app_path/_ah/api/registration/v1/uploadImage"); JSONObject jsonObject = new JSONObject(); jsonObject.put("image",stringEncodedImage); StringEntity stringEntity = new StringEntity(jsonObject.toString()); httpPost.addHeader("Content-Type", "application/json"); httpPost.setEntity(stringEntity); HttpResponse response = httpClient.execute(httpPost); 

在服务器端，在我的端点中，我这样做：

 @ApiMethod(name = "uploadImage", httpMethod = "POST") public JSONObject uploadImage(JSONObject request) throws IOException { String imageInString = (String) request.get("image"); Blob blob = new Blob(imageInString.getBytes()); ....save blob and do whatever you want... } 

反过来也是这样。 我将Blob打包到JsonObject中并将其发送出去。