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Java zip files from streams instantly without using byte[]

I want to compress multiples files into a zip files, I'm dealing with big files, and then download them into the client, for the moment I'm using this:
#RequestMapping(value = "/download", method = RequestMethod.GET, produces = "application/zip")
public ResponseEntity <StreamingResponseBody> getFile() throws Exception {
File zippedFile = new File("test.zip");
FileOutputStream fos = new FileOutputStream(zippedFile);
ZipOutputStream zos = new ZipOutputStream(fos);
InputStream[] streams = getStreamsFromAzure();
for (InputStream stream: streams) {
addToZipFile(zos, stream);
}
final InputStream fecFile = new FileInputStream(zippedFile);
Long fileLength = zippedFile.length();
StreamingResponseBody stream = outputStream - >
readAndWrite(fecFile, outputStream);
return ResponseEntity.ok()
.header(HttpHeaders.ACCESS_CONTROL_EXPOSE_HEADERS, HttpHeaders.CONTENT_DISPOSITION)
.header(HttpHeaders.CONTENT_DISPOSITION, "attachment;filename=" + "download.zip")
.contentLength(fileLength)
.contentType(MediaType.parseMediaType("application/zip"))
.body(stream);
}
private void addToZipFile(ZipOutputStream zos, InputStream fis) throws IOException {
ZipEntry zipEntry = new ZipEntry(generateFileName());
zos.putNextEntry(zipEntry);
byte[] bytes = new byte[1024];
int length;
while ((length = fis.read(bytes)) >= 0) {
zos.write(bytes, 0, length);
}
zos.closeEntry();
fis.close();
}
This take a lot of time before all files are zipped and then the downloading start, and for large files this kan take a lot of time, this is the line responsible for the delay:
while ((length = fis.read(bytes)) >= 0) {
zos.write(bytes, 0, length);
}
So is there a way to download files immediately while their being zipped ?

Try this instead. Rather than using the ZipOutputStream to wrap a FileOutputStream, writing your zip to a file, then copying it to the client output stream, instead just use the ZipOutputStream to wrap the client output stream so that when you add zip entries and data it goes directly to the client. If you want to also store it to a file on the server then you can make your ZipOutputStream write to a split output stream, to write both locations at once.
#RequestMapping(value = "/download", method = RequestMethod.GET, produces = "application/zip")
public ResponseEntity<StreamingResponseBody> getFile() throws Exception {
InputStream[] streamsToZip = getStreamsFromAzure();
// You could cache already created zip files, maybe something like this:
// String[] pathsOfResourcesToZip = getPathsFromAzure();
// String zipId = getZipId(pathsOfResourcesToZip);
// if(isZipExist(zipId))
// // return that zip file
// else do the following
StreamingResponseBody streamResponse = clientOut -> {
FileOutputStream zipFileOut = new FileOutputStream("test.zip");
ZipOutputStream zos = new ZipOutputStream(new SplitOutputStream(clientOut, zipFileOut));
for (InputStream in : streamsToZip) {
addToZipFile(zos, in);
}
};
return ResponseEntity.ok()
.header(HttpHeaders.ACCESS_CONTROL_EXPOSE_HEADERS, HttpHeaders.CONTENT_DISPOSITION)
.header(HttpHeaders.CONTENT_DISPOSITION, "attachment;filename=" + "download.zip")
.contentType(MediaType.parseMediaType("application/zip")).body(streamResponse);
}
private void addToZipFile(ZipOutputStream zos, InputStream fis) throws IOException {
ZipEntry zipEntry = new ZipEntry(generateFileName());
zos.putNextEntry(zipEntry);
byte[] bytes = new byte[1024];
int length;
while ((length = fis.read(bytes)) >= 0) {
zos.write(bytes, 0, length);
}
zos.closeEntry();
fis.close();
}
public static class SplitOutputStream extends OutputStream {
private final OutputStream out1;
private final OutputStream out2;
public SplitOutputStream(OutputStream out1, OutputStream out2) {
this.out1 = out1;
this.out2 = out2;
}
#Override public void write(int b) throws IOException {
out1.write(b);
out2.write(b);
}
#Override public void write(byte b[]) throws IOException {
out1.write(b);
out2.write(b);
}
#Override public void write(byte b[], int off, int len) throws IOException {
out1.write(b, off, len);
out2.write(b, off, len);
}
#Override public void flush() throws IOException {
out1.flush();
out2.flush();
}
/** Closes all the streams. If there was an IOException this throws the first one. */
#Override public void close() throws IOException {
IOException ioException = null;
for (OutputStream o : new OutputStream[] {
out1,
out2 }) {
try {
o.close();
} catch (IOException e) {
if (ioException == null) {
ioException = e;
}
}
}
if (ioException != null) {
throw ioException;
}
}
}
For the first request for a set of resources to be zipped you wont know the size that the resulting zip file will be so you can't send the length along with the response since you are streaming the file as it is zipped.
But if you expect there to be repeated requests for the same set of resources to be zipped, then you can cache your zip files and simply return them on any subsequent requests; You will also know the length of the cached zip file so you can send that in the response as well.
If you want to do this then you will have to be able to consistently create the same identifier for each combination of the resources to be zipped, so that you can check if those resources were already zipped and return the cached file if they were. You might be able to could sort the ids (maybe full paths) of the resources that will be zipped and concatenate them to create an id for the zip file.

Spring boot: Download zipped large files while they are being processed on the server

In my app I'm zipping and then downloading larges files, the files are located in azure, so I read the files from a stream and then zip them one after another, so I can dowload the zip file after all files has been zipped, here's my code:
#RequestMapping(value = "{analyseId}/download", method = RequestMethod.GET, produces = "application/zip")
public ResponseEntity<Resource> download(#PathVariable List<String> paths) throws IOException {
String zipFileName = "zipFiles.zip";
File zipFile = new File(zipFileName);
FileOutputStream fos = new FileOutputStream(zipFile);
ZipOutputStream zos = new ZipOutputStream(fos);
for (String path : paths) {
InputStream fis = azureDataLakeStoreService.readFile(path);
addToZipFile(path , zos, fis);
}
zos.close();
fos.close();
BufferedInputStream zipFileInputStream = new BufferedInputStream(new FileInputStream(zipFile.getAbsolutePath()));
InputStreamResource resource = new InputStreamResource(zipFileInputStream);
zipFile.delete();
return ResponseEntity.ok()
.header(HttpHeaders.ACCESS_CONTROL_EXPOSE_HEADERS, HttpHeaders.CONTENT_DISPOSITION)
.header(HttpHeaders.CONTENT_DISPOSITION, "attachment;filename=" + zipFileName)
.contentType(MediaType.parseMediaType("application/octet-stream"))
.body(resource);
}
private static void addToZipFile(String path, ZipOutputStream zos, InputStream fis) throws IOException {
ZipEntry zipEntry = new ZipEntry(FilenameUtils.getName(path));
zos.putNextEntry(zipEntry);
byte[] bytes = new byte[1024];
int length;
while ((length = fis.read(bytes)) >= 0) {
zos.write(bytes, 0, length);
}
zos.closeEntry();
fis.close();
}
However on azure the request time out is set to 230 sec, and cannot be changed, however for big files it takes more than that to load and then zip the files on the server, so the connection with the client will be lost meanwhile.
So my question is since I'm getting the data from a stream, can we do all these operations simultaneously, means getting the stream and download it as the same time and not waiting till getting the whole file, or if there any other idea can any body share it here please.
Thanks.

The answer is to not download the file to the server and then send it to the client but streaming it to the client directly here's the code
#RequestMapping(value = "/download", method = RequestMethod.GET)
public StreamingResponseBody download(#PathVariable String path) throws IOException {
final InputStream fecFile = azureDataLakeStoreService.readFile(path);
return (os) -> {
readAndWrite(fecFile, os);
};
}
private void readAndWrite(final InputStream is, OutputStream os)
throws IOException {
byte[] data = new byte[2048];
int read = 0;
while ((read = is.read(data)) >= 0) {
os.write(data, 0, read);
}
os.flush();
}
I also added this configuration to ApplicationInit:
#Configuration
public static class WebConfig extends WebMvcConfigurerAdapter {
#Override
public void configureAsyncSupport(AsyncSupportConfigurer configurer) {
configurer.setDefaultTimeout(-1);
configurer.setTaskExecutor(asyncTaskExecutor());
}
#Bean
public AsyncTaskExecutor asyncTaskExecutor() {
return new SimpleAsyncTaskExecutor("async");
}
}

Spring OutputStream - download pptx with IE

I use this Java code to download files from a web application:
#RequestMapping(value = "/filedownloads/filedownload/{userid}/{projectid}/{documentfileid}/{version}/", method = RequestMethod.GET)
public void filesDownload(final #PathVariable("userid") String userId, final #PathVariable("projectid") String projectId,
final #PathVariable("documentfileid") String documentFileId, final #PathVariable("version") String version,
final HttpServletResponse response) throws IOException, BusinessException {
...
final String fileName = "filename=" + documentFile.getFileName();
final InputStream is = new FileInputStream(filePath);
response.setHeader("Content-Disposition", "inline; " + fileName);
IOUtils.copy(is, response.getOutputStream());
response.flushBuffer();
}
if I will download a pptx- file I get the following IE- page:
What I want to do is to open the downloaded file in Powerpoint.
My question now would be if there is a header setting in order to open this file with the right application (in this case Powerpoint)

Simply try to set the Content Type header properly which is application/vnd.openxmlformats-officedocument.presentationml.presentation in case a pptx, as next:
response.setContentType(
"application/vnd.openxmlformats-officedocument.presentationml.presentation"
);
response.setHeader(
"Content-Disposition",
String.format("inline; filename=\"%s\"", documentFile.getFileName())
);
response.setContentLength((int) new File(filePath).length());
Here is the list of mime types corresponding to Office 2007 documents.

Here is a little sample code from a Spring MVC Controller:
#RequestMapping("/ppt")
public void downloadPpt(HttpServletRequest request, HttpServletResponse response) throws IOException {
Resource resource = new ClassPathResource("Presentation1.pptx");
InputStream resourceInputStream = resource.getInputStream();
response.setHeader("Content-Disposition", "attachment; filename=\"Presentation1.pptx\"");
response.setContentLengthLong(resource.contentLength());
byte[] buffer = new byte[1024];
int len;
while ((len = resourceInputStream.read(buffer)) != -1) {
response.getOutputStream().write(buffer, 0, len);
}
}
By setting the Content-Disposition to attachment, you're telling the browser to download this file as an attachment and by supplying the correct file name with extension, you're telling the Operating System to use whatever application the user normally uses to open a file of this type. In this case it will be MS Power Point.
This way you can get away with not knowing exactly what version of Power Point the file was created with.

I have tested code in IE-11 its work fine. See below code i.e
#RequestMapping(value = "/downloadfile", method = RequestMethod.GET)
#ResponseBody
public void downloadfile(HttpServletRequest request, HttpServletResponse response) throws Exception {
ServletOutputStream servletOutputStream = null;
try {
response.setContentType("application/octet-stream");
response.setHeader("Content-Disposition", "attachment; filename=downloadppt.pptx");
byte[] ppt = downloadFile();
servletOutputStream = response.getOutputStream();
servletOutputStream.write(ppt);
} catch (Exception e) {
throw e;
} finally {
servletOutputStream.flush();
servletOutputStream.close();
}
}
Generate bytes from saved pptx file.
public byte[] downloadFile() throws IOException {
InputStream inputStream = new FileInputStream(new File("e:/testppt.pptx"));
ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
// Transfer bytes from source to destination
byte[] buf = new byte[1024];
int len;
while ((len = inputStream.read(buf)) > 0) {
byteArrayOutputStream.write(buf, 0, len);
}
inputStream.close();
byteArrayOutputStream.close();
return byteArrayOutputStream.toByteArray();
}
That's it, you are able to download pptx file. Hope code help you, if you have any query or doubt then we can discuss or if any suggestions. Thank you

Why are InputStream instances closed when referenced within an ObservableMap?

I have ObservableMap in which resource files added.
private ObservableMap<String, InputStream> resourceFilesData;
resourceFilesData = new ObservableMapWrapper<String, InputStream>(
new HashMap<String, InputStream>()
);
And InputStreams added in such way:
resourceFilesData.put(f.getName(), new FileInputStream(f));
and finally when I want to use streams, they appear closed!
Why? I cant find reason.
Maybe, there some whey to handle moment, when stream get closed? (for debugging)
how streams are used:
private void pack() throws JAXBException, IOException {
HashMap<String, InputStream> resources = new HashMap<>();
byte[] buf = new byte[1024];
ZipOutputStream zos = new ZipOutputStream(new FileOutputStream("../" + fwData.getFileName() + ".iolfw"));
File xml = fwData.marshal();
InputStream xmlStream = new FileInputStream(xml);
resources.put(xml.getName(), xmlStream);
resources.putAll(resourceFilesData);
for (Map.Entry<String, InputStream> data: resources.entrySet()) {
InputStream input = data.getValue();
zos.putNextEntry(new ZipEntry(data.getKey()));
for (int readNum = 0; (readNum = input.read(buf)) != -1; ) {
zos.write(buf, 0, readNum);
}
zos.closeEntry();
input.close();
}
zos.close();
resources.remove(xmlStream);
xml.delete();
}
trace:
http://pastebin.com/hE21ECL9

I don't know the reason of that behaviour. But you can try to debug the problem using inherited class:
class FileInputStreamInh extends FileInputStream {
public FileInputStreamInh(File file) throws FileNotFoundException {
super(file);
}
#Override
public void close() throws IOException {
super.close();
^^^breakpoint here
}
}
So, instead of creation FileInputStream, you should create FileInputStreamInh.

Downloaded File Size 0

I'm trying here to add a specific dialog bean for action on Alfresco Explorer that supposed to download a specific docx file. The code is working fine when I hit the download action, it downloads the file but as mentioned in my question title, the file size is 0 bytes.
I'm using this to do that:
public class NewFormDialog extends BaseDialogBean {
protected String aspect;
protected String finishImpl(FacesContext context, String outcome)
throws Exception {
download(aspect);
// // get the space the action will apply to
// NodeRef nodeRef = this.browseBean.getActionSpace().getNodeRef();
//
// // resolve the fully qualified aspect name
// QName aspectToAdd = Repository.resolveToQName(this.aspect);
//
// // add the aspect to the space
// getNodeService().addAspect(nodeRef, aspectToAdd, null);
//
// // return the default outcome
return outcome;
}
public boolean getFinishButtonDisabled() {
return false;
}
public String getFinishButtonLabel() {
return "Download";
}
public void download(String pAspect) throws ServletException, IOException {
String filename = pAspect;
String filepath = "\\";
BufferedInputStream buf = null;
ServletOutputStream myOut = null;
try {
FacesContext fc = FacesContext.getCurrentInstance();
HttpServletResponse response = (HttpServletResponse) fc
.getExternalContext().getResponse();
myOut = response.getOutputStream();
File myfile = new File(filepath + filename);
// set response headers
response.setContentType("application/octet-stream");
response.addHeader("Content-Disposition", "attachment; filename="
+ filename);
response.setContentLength((int) myfile.length());
FileInputStream input = new FileInputStream(myfile);
buf = new BufferedInputStream(input);
int readBytes = 0;
// read from the file; write to the ServletOutputStream
while ((readBytes = buf.read()) != -1)
myOut.write(readBytes);
myOut.flush();
response.flushBuffer();
} catch (IOException ioe) {
throw new ServletException(ioe.getMessage());
} finally {
// close the input/output streams
if (myOut != null)
myOut.close();
if (buf != null)
buf.close();
FacesContext.getCurrentInstance().responseComplete();
}
}
public String getAspect() {
return aspect;
}
public void setAspect(String aspect) {
this.aspect = aspect;
}
}
I tried every solution that I found by none works.
Thank you in advance.

The File.length() method returns 0 if the file does not exist. Check to make sure that the file exists.
Tip: The Apache Commons IO library simplifies many I/O related tasks. For example, the following code snippet streams the contents of a file to the servlet response:
HttpServletResponse response = ...
File myfile = ...
InputStream in = null;
OutputStream out = null;
try {
in = new FileInputStream(myfile);
out = response.getOutputStream();
IOUtils.copy(in, out);
} finally {
IOUtils.closeQuietly(in); //checks for null
IOUtils.closeQuietly(out); //checks for null
}