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Exception : Stream is closed during downloading multiple attachments

I have requirement where a user can upload a file and later if other user see that he can download a file. New requirement suggest that now a user can upload multiple attachments and any user who see it can download multiple attachment as well.
So i took a list in which attachments are added and direct it to download controller, i changed the earlier line and kept a for-loop but during download only first attachment is downloaded and later it gives exception stream is closed.Below is the code of controller.Please let me know how can i over come this?
#ApiOperation(value = "Download content")
#RequestMapping(value = "/api/content/{id}/download/", method = RequestMethod.GET)
public ResponseEntity<String> downloadContent(HttpServletResponse response, #PathVariable("id") final Long id)
throws IOException, APIException {
Content content = null;
try {
content = this.contentService.get(this.contentUtils.getContentObject(id));
} catch (ServiceException e) {
throw new APIException("Access denied");
}
if (null == content) {
throw new APIException("Invalid content id");
}
List<Document> documentList = this.contentService.getDocumentByContent(content);
if (documentList != null && !documentList.isEmpty()) {
//Document document = documentList.get(0); //If multiple files supported?, then need to be handled here
for (Document document : documentList) {
File file = new File(document.getLocalFilePath());
if (file.exists()) {
response.setHeader("Content-Disposition", "attachment;filename=\"" + file.getName() + "\"");
try (InputStream inputStream = new FileInputStream(file); ServletOutputStream sos = response.getOutputStream();) {
IOUtils.copy(inputStream, sos);
} catch (final IOException e) {
LOGGER.error("File not found during content download" + id, e);
throw new APIException("Error during content download:" + id);
}
} else {
try {
s3FileUtil.download(document.getS3Url(), document.getLocalFilePath());
} catch (S3UtilException e) {
throw new APIException("Document not found");
}
}
}
} else {
//404
return new ResponseEntity<String>(HttpStatus.NOT_FOUND);
}
return new ResponseEntity<String>(HttpStatus.OK);
}

practically you cannot download all the files at once. Because, once you open a stream and write the file content to the stream, you have to close the stream.
When you add the files in for loop, you have to append the file content instead of file, which is not an expected behavior.
When you want to download multiple files at once, you have to zip
the files and download.
check this link: download multiple files

Download Google Docs file from Google Drive with java

I am trying to download a file from Google Drive. Download of a common file (pdf, jpg) went without any problem. But I can't get it to download Google files. I am getting an empty file without type and with size 0. Do you have any idea of what might cause this?
public InputStream download(String id) throws CloudServiceException {
try {
File file = service.files()
.get(id)
.execute();
String link = file.getExportLinks().get("application/pdf");
HttpResponse resp = service.getRequestFactory()
.buildGetRequest(
new GenericUrl(link))
.execute();
return resp.getContent();
} catch (HttpResponseException e) {
throw CloudServiceExceptionTransformer.transform(e, e.getStatusCode());
} catch(IOException ex) {
throw new InternalException(ex);
}
}

You need to use Export method for downloading google docs or any google files
String fileId = "1ZdR3L3qP4Bkq8noWLJHSr_iBau0DNT4Kli4SxNc2YEo";
OutputStream outputStream = new ByteArrayOutputStream();
driveService.files().export(fileId, "application/pdf")
.executeMediaAndDownloadTo(outputStream);

You can try this:
URL url = new URL("http://www.gaertner-servatius.de/images/sinnfrage/kapitel-2/spacetime.gif");
InputStream inStream = url.openStream();
Files.copy(inStream, Paths.get("foobar.gif"), StandardCopyOption.REPLACE_EXISTING);
inStream.close();

Try this:
com.google.api.services.drive.Drive service;
static InputStream download(String id) {
if (service != null && id != null) try {
com.google.api.services.drive.model.File gFl =
service.files().get(id).setFields("downloadUrl").execute();
if (gFl != null){
return service.getRequestFactory()
.buildGetRequest(new GenericUrl(gFl.getDownloadUrl())).execute().getContent());
}
} catch (Exception e) { e.printStackTrace(); }
return null;
}
Good Luck

So the problem was in fact in building of a response. Google files have a size 0 and google media type was not recognized which resulted in this broken file.
Edit: Here is my working version. I removed the set size so that it downloads those 0 sized files.
ResponseEntity.BodyBuilder builder = ResponseEntity.status(HttpStatus.OK)
.header(HttpHeaders.CONTENT_DISPOSITION, encoding)
.contentType(MediaType.parseMediaType(resource.getMimeType()));
return builder.body(new InputStreamResource(resource.getContent()));

Reading a file from a Res folder

I have put a file "template.html" inside RAW folder and I want to read it into a InputStream. But it is returning me null. Can't understand what is wrong in the below code
e.g. fileName passed as parameter is "res/raw/testtemplate.html"
public String getFile(String fileName) {
InputStream input = this.getClass().getClassLoader().getResourceAsStream(fileName);
return getStringFromInputStream(input);
}
Also, there might be a better solution by putting these files in a particular subfolder and putting it inside Asset folder but then I believe I would need to pass context in AssetManager. I don't understand that solution, sorry I am new to android development. Can someone shed some light regarding how this approach can be achieved.
EDIT
I have started implementing this solution with Assets. Below method is supposed to return a string containing the entire text of the file stored as template.html.
getFile("template.html") // I am sending extension this time
Problem getting error getAssets() is undefined.
public String getFile(String fileName) {
BufferedReader reader = null;
StringBuilder sb = new StringBuilder();
String line;
try {
reader = new BufferedReader(new InputStreamReader(getAssets().open(fileName)));
while ((line = reader.readLine()) != null) {
sb.append(line);
}
}
catch (IOException e) {
e.printStackTrace();
} finally {
if (reader != null) {
try {
reader.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
return sb.toString();
}

use this
new BufferedInputStream(getResources().openRawResource(filepath));
this will return a buffered input stream

The file name should be without extension :
InputStream ins = getResources().openRawResource(
getResources().getIdentifier("raw/FILENAME_WITHOUT_EXTENSION",
"raw", getPackageName()));

For this purposes uses assets folder:
assets/
This is empty. You can use it to store raw asset files. Files that you save here are compiled into an .apk file as-is, and the original filename is preserved. You can navigate this directory in the same way as a typical file system using URIs and read files as a stream of bytes using the AssetManager. For example, this is a good location for textures and game data.
So, you could easy get access at assets with context: context.getAssets()
BufferedReader reader = null;
try {
reader = new BufferedReader(
new InputStreamReader(context.getAssets().open("filename.txt")));
}
} catch (IOException e) {
//log the exception
} finally {
if (reader != null) {
try {
reader.close();
} catch (IOException e) {
//log the exception
}
}
}

Can't load sound files LibGdx

I would like to load files directly from expansion OBB file by using AssetManager. I implemented my own FileHandleResolver
public class CustomFileHandleResolver implements FileHandleResolver
{
#Override
public FileHandle resolve(String fileName) {
return new CustomFileHandle(fileName);
}
}
I set it to my AssetManager. I created my own FileHandle and I override read() function
#Override
public InputStream read()
{
InputStream input = null;
try {
input = GameInfo.expansionFile.getInputStream(file.getPath().replace('\\', '/'));
} catch (IOException e) {
e.printStackTrace();
}
return input;
}
It loads all the files like .PNG, .PACK, .FNT, except .OGG files, so I guess that all sound files won't be loaded. I'm getting this error:
com.badlogic.gdx.utils.GdxRuntimeException: com.badlogic.gdx.utils.GdxRuntimeException: Couldn't load dependencies of asset: SFx/button_click.ogg
And this error:
com.badlogic.gdx.utils.GdxRuntimeException: java.lang.ClassCastException: com.solidgamesstudio.threedefendersn.framework.CustomFileHandle cannot be cast to com.badlogic.gdx.backends.android.AndroidFileHandle
I read that zip can not be compressed. In 7zip I selected compression to "Store" so that it's not compressed at all, but still this problem occurs.
I traversed what is happening when files are being loaded and I found that AssetManager calls my CustomFileHandleResolver which creates CustomFileHandle. For every file that is not .OGG it calls InputStream read(). In this function it loads the file from the zip and it's fine. But as I said when it comes to loading .OGG it doesn't call this function. So it's not even trying yet to get the file from the zip. Question is, why .OGG file doesn't call InputStream read() in CustomFileHandle()?
UPDATE
I traversed more and I found out that it won't call InputStream read() because it can't create a Sound from FileHandle somehow. Clue to this is
CustomFileHandle cannot be cast to AndroidFileHandle
While to create a sound you need to pass fileHandle.
public Sound newSound (FileHandle fileHandle);
This is called from SoundLoader
#Override
public void loadAsync (AssetManager manager, String fileName, FileHandle file, SoundParameter parameter) {
sound = Gdx.audio.newSound(file);
}
And that soundLoader uses my CustomFileHandleResolver. I don't know if Sounds are handled differently then other types of files. But by default AssetManager uses
public class InternalFileHandleResolver implements FileHandleResolver {
#Override
public FileHandle resolve (String fileName) {
return Gdx.files.internal(fileName);
}
}
I can't get into Gdx.files.internal to see if there are any special handling for Sounds.
UPDATE
Further analysis give me clue that the main problem is this as mentioned before.
CustomFileHandle cannot be cast to AndroidFileHandle
I don't know why it's casting my FileHandle to AndroidFileHandle while loading OGG file. If it loads fine other type of files, that probably means it doesn't do casting for them. That means that OGG is special and it needs casting. Any clues?

I have not found a way to load sound files from the zip file. Problem is that AssetManager loads sound files differently than other file types. Problem was that it is casting FileHandle to AndroidFileHandle, and since CustomFileHandle extends FileHandle it's impossible to cast it to AndroidFileHandle. I found no way to go around this, because it's deeply rooted.
CustomFileHandle cannot be cast to AndroidFileHandle
In this situation I had to take out all sound files from the OBB file and put them together with the app. I created another instance of AssetManager just for loading sounds. So, sounds are loaded normally as you would with AssetManager and for any other type of file I used AssetManager that uses my own FileHandlerResolver which uses my own FileHandle class that returns a file from the zip. The only problem with this approach is that you are limited to having sounds files only up to 50 MB.

I solved this problem extracting the zip to a specific folder,
and then reading from that external folder.
The extraction of the zip is done by these methods:
public void extract(){
String packageName = getPackageName();
File root = Environment.getExternalStorageDirectory();
File expPath = new File(root.toString() + "/Android/obb/" + packageName);
if (expPath.exists()) {
String strMainPath = null;
try {
strMainPath = expPath + File.separator + "main."
+ getPackageManager().getPackageInfo(
getPackageName(), 0).versionCode + "."
+ packageName + ".obb";
Log.e("Extract File path", "===>"+strMainPath);
File f=new File(strMainPath);
if(f.exists()){
Log.e("Extract From File path", "===> not exist");
}
else
{
Log.e("Extract From File path", "===> exist");
}
String pathToExtract = Environment.getExternalStorageDirectory()+"/"+Cons.FOLDERNAME;
Log.e("Extract to path", "===>"+pathToExtract);
flag = extractZip(strMainPath,pathToExtract);
Log.e("After Extract Zip", "===>"+flag);
} catch (NameNotFoundException e) {
e.printStackTrace();
}
}
}
private boolean extractZip(String pathOfZip,String pathToExtract)
{
int BUFFER_SIZE = 1024;
int size;
byte[] buffer = new byte[BUFFER_SIZE];
try {
File f = new File(pathToExtract);
if(!f.isDirectory()) {
f.mkdirs();
}
ZipInputStream zin = new ZipInputStream(new BufferedInputStream(new FileInputStream(pathOfZip), BUFFER_SIZE));
fileNum=0;
try {
ZipEntry ze = null;
while ((ze = zin.getNextEntry()) != null) {
String path = pathToExtract +"/"+ ze.getName();
if (ze.isDirectory()) {
File unzipFile = new File(path);
if(!unzipFile.isDirectory()) {
unzipFile.mkdirs();
}
}
else {
updateFileNum();
FileOutputStream out = new FileOutputStream(path, false);
BufferedOutputStream fout = new BufferedOutputStream(out, BUFFER_SIZE);
try {
while ( (size = zin.read(buffer, 0, BUFFER_SIZE)) != -1 ) {
fout.write(buffer, 0, size);
}
zin.closeEntry();
}catch (Exception e) {
Log.e("Exception", "Unzip exception 1:" + e.toString());
}
finally {
fout.flush();
fout.close();
}
}
}
}catch (Exception e) {
Log.e("Exception", "Unzip exception2 :" + e.toString());
}
finally {
zin.close();
}
return true;
}
catch (Exception e) {
Log.e("Exception", "Unzip exception :" + e.toString());
}
return false;
}
Note: Extract it to .Android folder, otherwhise users will have direct acces to the assets. For example they will see the images in the Gallery app.

Well, I'm doing this currently. Whenever you need to get a real FileHandle in order for the sound loading mechanism to work (or in any other case were the casting to AndroidFileHandle is bothering you), unzip that file to a local directory and reuse it if needed:
public static FileHandle getRealFileHandle(String zipEntryPath, ZipFile zipFile) {
if (Gdx.files.local(zipEntryPath).exists()) {
return Gdx.files.local(zipEntryPath);
} else {
Gdx.app.log(TAG, "Unzipping file '" + zipEntryPath + "'...");
try {
FileHandle unzippedFile;
ZipEntry entry = zipFile.getEntry(zipEntryPath);
if (entry != null) {
unzippedFile = Gdx.files.local(zipEntryPath);
InputStream is = zipFile.getInputStream(entry);
byte[] buffer = new byte[65536];
int readLength;
while ((readLength = is.read(buffer)) >= 0) {
unzippedFile.writeBytes(buffer, 0, readLength, true);
}
return unzippedFile;
} else {
Gdx.app.error(TAG, "Entry '" + zipEntryPath + "' not found inside zip file.");
}
} catch (IOException ioe) {
Gdx.app.error(TAG, "A problem occurred while writing to the local file.");
}
}
return null;
}

ObjectOutputStream throws ObjectOutputStream in a java web server

I'm trying to write a simplest java web server program following an instruction which is only able to handle GET inquiry. The main idea is to get an ObjectOutputStream from a socket, use an ObjectInputStream to open a local file and write it into the ObjectOutputStream byte by byte.
The serve() is attached below. It takes an ObjectOutputStream I want to write to and the path to a file as parameters.
public void serve(ObjectOutputStream out, String path) throws IOException {
System.out.println("Trying to serve: " + path);
File file = new File(path);
if (!file.exists()) {
//return an HTTP 404
} else {
out.writeBytes("HTTP/1.1 200 OK\n\n");
ObjectInputStream in = null;
try {
in = new ObjectInputStream(new FileInputStream(file));
int data;
while ((data = in.readByte()) != -1) {
out.writeByte((byte) data);
}
System.out.println("Request valid.");
} catch (IOException e) {
System.out.println("Error in serve(): sending file: " + e.getMessage());
} finally {
if (null != in)
in.close();
}
}
}
However, when I use browser to access localhost:8080 (the port is at 8080), it throws an IOException
invalid stream header: 3C68746D
I believe it's in out.writeByte((byte) data); step. Can you tell me why and how to fix it? Thanks ahead.

ObjectInputStream and ObjectOutputStream are used for object serialization in java.
Please refer the below article to understand the usage of these streams.
http://java.sun.com/developer/technicalArticles/Programming/serialization/
For your code, you could better use BufferedInputStream and BufferedOutputStream wherever you find corresponding Object Stream.