[英]uploading a file with DataOutputStream doesn't display real progress
我正在使用DataOutputStream通過以下代碼將文件從android上傳到我的網絡服務器:
public class SnapshotUploadTask extends AsyncTask<Object, Integer, Void> {
private final File file;
private final ProgressDialog progressDialog;
private final Activity activity;
public SnapshotUploadTask(File file, ProgressDialog progressDialog, Activity activity) {
this.progressDialog = progressDialog;
this.file = file;
this.activity = activity;
}
@Override
protected void onPreExecute() {
progressDialog.setProgress(0);
}
@Override
protected Void doInBackground(Object... arg0) {
String lineEnd = "\r\n";
String twoHyphens = "--";
String boundary = "*****";
int bytesRead;
int bytesAvailable;
int bufferSize;
byte[] buffer;
int maxBufferSize = 1 * 512;
try {
FileInputStream fileInputStream = new FileInputStream(file);
URL url = new URL("http://bla.bla.bla/upload");
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
connection.setDoInput(true);
connection.setDoOutput(true);
connection.setUseCaches(false);
connection.setRequestMethod("POST");
connection.setRequestProperty("Connection", "Keep-Alive");
connection.setRequestProperty("ENCTYPE", "multipart/form-data");
connection.setRequestProperty("Content-Type", "multipart/form-data;boundary=" + boundary);
connection.setRequestProperty("uploaded_file", file.getName());
DataOutputStream dataOutputStream = new DataOutputStream(connection.getOutputStream());
dataOutputStream.writeBytes(twoHyphens + boundary + lineEnd);
dataOutputStream.writeBytes("Content-Disposition: form-data; name=\"uploaded_file\";filename=\"" + file.getName() + "\"" + lineEnd);
dataOutputStream.writeBytes(lineEnd);
bytesAvailable = fileInputStream.available();
final int hundredPercent = bytesAvailable;
progressDialog.setMax(hundredPercent);
bufferSize = Math.min(bytesAvailable, maxBufferSize);
buffer = new byte[bufferSize];
bytesRead = fileInputStream.read(buffer, 0, bufferSize);
while (bytesRead > 0) {
dataOutputStream.write(buffer, 0, bufferSize);
bytesAvailable = fileInputStream.available();
bufferSize = Math.min(bytesAvailable, maxBufferSize);
bytesRead = fileInputStream.read(buffer, 0, bufferSize);
final int restBytes = bytesAvailable;
final int uploadedBytes = hundredPercent - restBytes;
activity.runOnUiThread(new Runnable() {
@Override
public void run() {
progressDialog.setProgress((int) uploadedBytes);
if (restBytes <= 0) {
progressDialog.setMessage(activity.getString(R.string.camera_uploading_done));
}
}
});
}
dataOutputStream.writeBytes(lineEnd);
dataOutputStream.writeBytes(twoHyphens + boundary + twoHyphens + lineEnd);
int serverResponseCode = connection.getResponseCode();
String serverResponseMessage = connection.getResponseMessage();
if (serverResponseCode == 200) {
progressDialog.dismiss();
}
fileInputStream.close();
dataOutputStream.flush();
dataOutputStream.close();
} catch (Exception e) {
progressDialog.dismiss();
}
return null;
}
@Override
protected void onPostExecute(Void result) {
progressDialog.dismiss();
}
}
現在發生的事情是,一旦我在OutputStream中寫入了一定數量的字節,便立即更新我的progressDialog,這導致ProgressDialog在服務器實際接收到數據之前達到100%。
我僅在到達connection.getResponseCode();
時才知道傳輸完成的時間connection.getResponseCode();
我想要的是在服務器實際接收到數據塊時更新進度。 有沒有辦法做到這一點?
您需要知道HttpURLConnection
緩沖所有輸出,除非您設置固定長度或分塊傳輸模式,您一定要這樣做,而不是自己實現它。 這樣可以正確設置Content-Length標頭。 如果您使用這些傳輸模式之一,則沒有緩沖。
注意:您正在濫用available()
:請參閱Javadoc; 在大多數情況下,您正在編寫垃圾郵件:
dataOutputStream.write(buffer, 0, bufferSize);
應該
dataOutputStream.write(buffer, 0, bytesRead);
您也不需要在讀取循環內擺弄available()
。 這樣的事情就足夠了:
long total = 0;
int maxBufferSize = 8192; // at least. 512 is far too small.
while ((bytesRead = fileInputStream.read(buffer, 0, bufferSize)) > 0) {
dataOutputStream.write(buffer, 0, bytesRead);
total += bytesRead;
final long uploadedBytes = total;
activity.runOnUiThread(new Runnable() {
@Override
public void run() {
progressDialog.setProgress(uploadedBytes);
}
});
}
}
// at this point we are at end of stream
activity.runOnUiThread(new Runnable() {
@Override
public void run() {
progressDialog.setMessage(activity.getString(R.string.camera_uploading_done));
}
}
E&OE
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