We Keep Coding

Why Resume Downloading downloads corrupted file in Java Application?

In My Struts base Java web application , I have implemented download functionality with pause/resume. let me explain how my download works , actually file (e.g. image file, doc) will be converted to pdf in the server then it will start downloading , then without pause, it has successfully downloaded file and its not corrupted but when I pause and resume it downloads file successfully but it will be corrupted pdf. I can't figure what I am missing . My Code is as below
{ in = new FileInputStream(f);
int DOWNLOAD_BUFFER_SIZE = Integer.parseInt(CacheManagement.getInstance().getSystemPropertyByAlias().get("DOWNLOAD_BUFFER_SIZE").getPropertyValue());
response.setHeader("Accept-Ranges", "bytes");
response.setContentType("application/x-download");
response.setHeader("Content-Disposition", "attachment; filename=\"" + fileName + "\"");
response.setBufferSize(DOWNLOAD_BUFFER_SIZE);
// SimpleDateFormat formatter = new SimpleDateFormat("EEE, d MMM yyyy HH:mm:ss Z");
// Date lastModifiedDate = formatter.parse(String.valueOf(f.lastModified()));
Date lastModifiedDate = new Date(f.lastModified());
response.setHeader("ETag", f.length() + "_" + lastModifiedDate.getTime());
response.setDateHeader("Last-Modified", lastModifiedDate.getTime());
String range = request.getHeader("Range");
if (range != null && !range.isEmpty())
{
ArrayList<Range> ranges = getRangeList(range, f.length());
Range r = ranges.get(0);
response.setHeader("Content-Range", "bytes " + r.getStart() + "-" + r.getEnd() + "/" + r.getTotal());
response.setHeader("Content-Length", String.valueOf(r.getLength()));
response.setStatus(HttpServletResponse.SC_PARTIAL_CONTENT);
}
else
{
response.setHeader("Content-Length", String.valueOf(f.length()));
response.setHeader("Content-Range", "bytes 0-" + (f.length() - 1) + "/" + f.length());
}
o = response.getOutputStream();
buf = new BufferedInputStream(in);
byte[] dataBytes = new byte[DOWNLOAD_BUFFER_SIZE];
int readed = 0;
while ((readed = buf.read(dataBytes)) != -1)
{
try
{
o.write(dataBytes, 0, readed);
}
catch (Exception e)
{
// System.out.println("-- Client Aborted Download --");
logger.error("-- Client Aborted Download --");
break;
}
}

Don't use buf = new BufferedInputStream(in); to read remaining bytes, you need to use RandomAccessFile class and seek() method to start download with remaining bytes.
RandomAccessFile raFile = new RandomAccessFile(f, "r");
o = response.getOutputStream();
// buf = new BufferedInputStream(in);
byte[] dataBytes = new byte[DOWNLOAD_BUFFER_SIZE];
int readed;
raFile.seek(r.getStart());
while ((readed = raFile.read(dataBytes)) != -1)
{
try
{
o.write(dataBytes, 0, readed);
}
catch (Exception e)
{
logger.error("-- Client Aborted Download --");
break;
}
}

How to detect uris from moved files

Anyone knows how to detect uris from moved files programmatically in Java/Android?When I start the app I detect all images in my phone (with their uris, path....), if I move the images with a media manager, next time I start the app I can get the whole uris again, with the new path. But, if I move these images programmatically (copying the image and deleting the image from the original path) next time I start the app the uris will be the previous path a not the new one. I'm trying to fix deleting the app cache, but doesn't work. Anyone knows what can be happen?
I tried to move the files with two functions and I have same problem:
public static void moveFile(ArrayList<ImagesData> images) throws IOException {
for (int i = 0; i < images.size(); i++) {
File file_Source = new File(images.get(i).imagePath);
File file_Destination = new File(Environment.getExternalStorageDirectory() + "/PrivateGallery/" + new File(images.get(i).imagePath).getName());
FileChannel source = null;
FileChannel destination = null;
try {
source = new FileInputStream(file_Source).getChannel();
destination = new FileOutputStream(file_Destination).getChannel();
Log.i(TAG, "Source " + source + " destination " + destination);
long count = 0;
long size = source.size();
while((count += destination.transferFrom(source, count, size-count)) < size);
//destination.transferFrom(source, 0, source.size());
file_Source.delete();
}
finally {
if(source != null) {
source.close();
}
if(destination != null) {
destination.close();
}
}
}
}
public void changeToNewPath(ArrayList<ImagesData> images) {
String outputPath = Environment.getExternalStorageDirectory() + "/PrivateGallery/";
//TODO COMPROBAR SI EXISTE YA UN ARCHIVO CON SU NOMBRE
InputStream in = null;
OutputStream out = null;
for(int i = 0; i < images.size(); i++) {
try { //TODO revisar lod el cambio de directorio
//create output directory if it doesn't exist
//File dir = new File(outputPath);
File f = new File(images.get(i).imagePath);
String a = f.getName();
Log.e(TAG, a);
in = new FileInputStream(images.get(i).imagePath);
out = new FileOutputStream(outputPath + new File(images.get(i).imagePath).getName());
byte[] buffer = new byte[1024];
int read;
while ((read = in.read(buffer)) != -1) {
out.write(buffer, 0, read);
}
in.close();
in = null;
// write the output file
out.flush();
out.close();
out = null;
// delete the original file
new File(images.get(i).imagePath).delete();
} catch (FileNotFoundException fnfe1) {
Log.e("tag", fnfe1.getMessage());
} catch (Exception e) {
Log.e("tag", e.getMessage());
}
}
}

Android - File Corrupts while saving

I am saving a file to disk after downloading it from server, but I believe it gets corrupted while saving on the disc. If the same file is downloaded using chrome on mac or using any other method, the file downloads and reads normally. The corruption seems to be in the saving process of the file. I am adding the code to help find out the problem. The file is a css file.
Corruption:
Some whitespace sort of characters appear when reading the file. A surprising thing that I tried and noticed is that if I reduce the BUFFER_SIZE to 32 from 4096, the file does not get corrupt, I couldn't figure out why. Also, reducing BUFFER_SIZE reduces whitespaces / corrupted characters.
Appreciate any pointers in the right direction. Thanks
private static final int BUFFER_SIZE = 4096;
// saves file to disk and returns the contents of the file.
public static String downloadFile(Context context, String filePath, String destParent) {
String content = null;
StringBuilder sb = new StringBuilder();
HttpURLConnection connection = null;
InputStream is = null;
FileOutputStream os = null;
String sUrl = Urls.makeWebAssetUrl(filePath); /// consider this my file URL
String destFile = getContextBaseDir(context) + (destParent != null ? File.separator + destParent : "") + File.separator + filePath;
try {
URL url = new URL(sUrl);
connection = (HttpURLConnection) url.openConnection();
connection.connect();
int responseCode = connection.getResponseCode();
if (responseCode == HttpURLConnection.HTTP_OK) {
File outFile = new File(destFile);
if (!outFile.getParentFile().exists()) {
if (!outFile.getParentFile().mkdirs()) {
throw new RuntimeException("Unable to create parent directories for " + filePath);
}
}
is = connection.getInputStream();
os = new FileOutputStream(outFile);
int bytesRead = 0;
byte[] buffer = new byte[BUFFER_SIZE];
while ((bytesRead = is.read(buffer)) != -1) {
sb.append(new String(buffer, 0, bytesRead, DEFAULT_ENCODING));
os.write(buffer);
}
content = sb.toString();
}
else {
LogUtils.LOGW(TAG, responseCode + " while connecting to " + sUrl + ": " + connection.getResponseMessage());
}
} catch(Exception e) {
LogUtils.LOGE(TAG, "Error while downloading " + sUrl, e);
} finally {
if (is != null) {
try {
is.close();
} catch (IOException e) {
LogUtils.LOGE(TAG, "Error closing inputStream while downloading " + sUrl, e);
}
}
if (os != null) {
try {
os.flush();
} catch (IOException e) {
LogUtils.LOGE(TAG, "Error flushing outputStream while downloading " + sUrl, e);
}
try {
os.close();
} catch (IOException e) {
LogUtils.LOGE(TAG, "Error closing outputStream while downloading " + sUrl, e);
}
}
}
return content;
}

os.write(buffer);
The problem is here. It should be:
os.write(buffer, 0, bytesRead);
I don't know why you are also accumulating the content in a StringBuffer and returning it as a String. That won't scale, and in any cast it's redundant. Remove.

Creation of GIF is taking so long time in Android

I am creating a app which burst capture images and create a GIF as output. My problem is creation of GIF from the image sequence is taking so long time, whether the resolution of images are 320x240. I am using AnimatedGifEncoder class for GIF encoding. as follow this link.
My code for creation of GIF is as following
private void saveGifImage() {
FileOutputStream outStream =
String fileName = "test.gif";
try {
File file = new File(Environment.getExternalStorageDirectory() + "/gif_convertor/sample/");
if (!file.exists())
file.mkdirs();
File file1 = new File(file + File.separator +
if (file1.exists()) {
} else {
try {
// file1.mkdirs();
file1.createNewFile();
} catch (Exception e) {
}
}
outStream = new FileOutputStream(file1);
Log.d("Location", file1.getPath().toString());
outStream.write(generateGIF());
outStream.close();
} catch (Exception e) {
e.printStackTrace();
} finally {
DialogUtils.stopProgressDisplay();
}
}
private byte[] generateGIF() {
ByteArrayOutputStream bos = new ByteArrayOutputStream();
AnimatedGifEncoder encoder = new AnimatedGifEncoder();
encoder.start(bos);
encoder.delay = 33; // 50 means 0.5 seconds ( 100 value is equivalent to 1 seconds)
encoder.repeat = 0; // 0 means repeat forever, other n positive integer means n times repeat , -1 means no repeat
encoder.sizeSet = true; // resize allowed with true flag
encoder.width = 320;
encoder.height = 240;
File tempDir = new File(getActivity().getExternalFilesDir(null), "temp");
if (tempDir.exists()) {
for (File file : tempDir.listFiles()) {
Bitmap bitmap = BitmapFactory.decodeFile(file.getAbsolutePath());
encoder.addFrame(bitmap);
}
}
encoder.finish();
return bos.toByteArray();
}

Android:"Unexpected end of stream" exception downloading large files

I am building an Android Application and I need to download a file from a url, which is 33 MB large.
Here the download task:
try {
int MAX_BUFFER_SIZE = 4096;
URL mUrl = new URL(params[0]);
HttpURLConnection connection = (HttpURLConnection) mUrl.openConnection();
connection.setRequestMethod("GET");
long length = connection.getContentLength(), downloaded = 0;
int read;
byte [] buffer = new byte[(((int)length) > MAX_BUFFER_SIZE) ? MAX_BUFFER_SIZE : (int)length];
String filename = getFilename(mUrl);
File file = new File (SDCARD_ROOT);
if (!file.exists() || !file.isDirectory()){
file.mkdir();
}
this.filename = filename;
file = new File (SDCARD_ROOT + this.filename);
FileOutputStream fos = new FileOutputStream (file);
//Start downloading
InputStream stream = connection.getInputStream();
while ((read=stream.read(buffer)) > -1){
fos.write(buffer, 0, read);
downloaded += read;
publishProgress((int) ((float) downloaded/length * 100));
}
fos.close();
return 1;
} catch (Exception e){
Log.e("REV-PARTS", "Revolver parts error in DownloadTask: " + e.getMessage());
return 2;
}
It works right with small files (1-15 MB), but it will return a "unexpected end of stream" exception with large files.

Setting a chunk size seemed to work for me.
connection.setChunkedStreamingMode(1048576);

For large files you need to set the connection time out manually by using the following code.
I have set the time out to 3 minutes
connection.setConnectTimeout(180000);
connection.setReadTimeout(180000);

While you catch the exception, I try the method downContinue(). I can show my code:
private void downloadApk() {
thread1 = new Thread() {
public void run() {
File oFile = null;
try {
URL url = new URL(PQGLApplication.resrootURL + "apk/PQGLMap.apk");
HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
ReadableByteChannel channel =
Channels.newChannel(urlConnection.getInputStream());
oFile =
new File(Environment.getExternalStorageDirectory().getAbsolutePath()
+ "/" + "hy_ht_new/" + "test2" + ".apk");
oFile.setWritable(true);
oFile.setReadable(true);
if (oFile.exists()) {
oFile.delete();
}
FileOutputStream fos = new FileOutputStream(oFile);
fileSize = urlConnection.getContentLength();
ByteBuffer buffer = ByteBuffer.allocate(1024);
int noOfBytes = 0;
byte[] data = null;
sendApkMessage(0, 0);
while ((noOfBytes = channel.read(buffer)) > 0) {
data = new byte[noOfBytes];
System.arraycopy(buffer.array(), 0, data, 0, noOfBytes);
buffer.clear();
fos.write(data, 0, noOfBytes);
downLoadFileSize += noOfBytes;
sendApkMessage(1, downLoadFileSize);
}
fos.flush();
fos.close();
channel.close();
sendApkMessage(2, oFile.getAbsolutePath());
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
downContinue();
}
};
};
thread1.start();
}
private void downContinue() {
continueTime++;
try {
if (continueTime == 3) {
continueTime = 0;
sendApkMessage(4, 0);
Log.e("what is the continuetime", "continueTime" + continueTime);
} else {
URL url = new URL(PQGLApplication.resrootURL + "apk/PQGLMap.apk");
HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
File oFile =
new File(Environment.getExternalStorageDirectory().getAbsolutePath() + "/"
+ "hy_ht_new/" + "test2" + ".apk");
RandomAccessFile oSavedFile = new RandomAccessFile(oFile, "rw");
FileOutputStream fos = new FileOutputStream(oFile);
ReadableByteChannel channel = Channels.newChannel(urlConnection.getInputStream());
// oSavedFile.seek(nPos);
ByteBuffer buffer = ByteBuffer.allocate(1024);
byte[] data = null;
int temp = 0;
sendApkMessage(3, oFile.getAbsolutePath());
while ((temp = channel.read(buffer)) > 0) {
data = new byte[temp];
System.arraycopy(buffer.array(), 0, data, 0, temp);
buffer.clear();
fos.write(data, 0, temp);
}
fos.flush();
fos.close();
oSavedFile.close();
sendApkMessage(2, oFile.getAbsolutePath());
continueTime = 0;
}
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
Log.e("what is the exception", e.toString() + continueTime);
downContinue();
}
}
This downContinue method is used to solve this problem. At least, the file is downloaded successfully!