我想從Android上的相機捕獲圖像,並將其發送到Google App Engine,該應用程序將圖像存儲在blob存儲區中。聽起來很簡單,我可以獲得多部分POST到GAE,但存儲到Blob存儲需要servlet返回一個HTTP重定向(302)。所以,我需要一個可以在執行HTTP POST之後遵循重定向的連接。這裏是我的代碼WISH將工作:最佳方法:從Android到GAE的HTTP POST(多部分)
public static String sendPhoto(String myUrl, byte[] imageData) {
HttpURLConnection connection = null;
DataOutputStream outputStream = null;
String pathToOurFile = "/data/file_to_send.jpg";
String urlServer = myUrl;
String lineEnd = "\r\n";
String twoHyphens = "--";
String boundary = "*****";
// Please follow redirects
HttpURLConnection.setFollowRedirects(true);
BufferedReader rd = null;
StringBuilder sb = null;
String line = null;
try {
URL url = new URL(urlServer);
connection = (HttpURLConnection) url.openConnection();
// Allow Inputs & Outputs
connection.setDoInput(true);
connection.setDoOutput(true);
connection.setUseCaches(false);
// I really want you to follow redirects
connection.setInstanceFollowRedirects(true);
connection.setConnectTimeout(10000); // 10 sec
connection.setReadTimeout(10000); // 10 sec
// Enable POST method
connection.setRequestMethod("POST");
connection.setRequestProperty("Connection", "Keep-Alive");
connection.setRequestProperty("Content-Type",
"multipart/form-data;boundary=" + boundary);
connection.connect();
outputStream = new DataOutputStream(connection.getOutputStream());
outputStream.writeBytes(twoHyphens + boundary + lineEnd);
outputStream
.writeBytes("Content-Disposition: form-data; name="
+ "\"file1\";filename=\""
+ pathToOurFile + "\"" + lineEnd);
outputStream.writeBytes(lineEnd);
outputStream.write(imageData);
outputStream.writeBytes(lineEnd);
outputStream.writeBytes(twoHyphens + boundary + twoHyphens
+ lineEnd);
outputStream.flush();
outputStream.close();
rd = new BufferedReader(new InputStreamReader(
connection.getInputStream()));
sb = new StringBuilder();
while ((line = rd.readLine()) != null) {
sb.append(line + '\n');
}
Log.i("Response: ", sb.toString());
// Responses from the server (code and message)
int serverResponseCode = connection.getResponseCode();
String serverResponseMessage = connection.getResponseMessage();
Log.i("Response: serverResponseCode:",
String.valueOf(serverResponseCode));
Log.i("Response: serverResponseMessage:", serverResponseMessage);
} catch (Exception ex) {
ex.printStackTrace();
}
}
雖然我試試,這個代碼將不會跟隨重定向。輸入的蒸汽總是空的,響應始終爲302.雖然圖像上傳得很好。如果有人能告訴我我能做些什麼來使它遵循重定向,所以我可以閱讀回覆,我真的很感激。
或者,如果有更好的方法,我很樂意聽到它。我知道有像Apache HTTP Client那樣的庫,但它需要很多的依賴關係,這對於一個簡單的任務來說似乎過於膨脹。
謝謝
你確實需要關注重定向嗎?如果您只需要知道圖像上傳成功,您只需檢查是否返回了正確的重定向。 – 2010-07-19 11:14:45
是的,我需要遵循重定向。你看,當圖像上傳到Blobstore時,會生成一個ID。爲了引用圖像,您需要在某處記錄該ID,這是由於重定向而在Servlet中發生的。 – 2010-07-19 18:21:55