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Extracting PDF inside a Zip inside a Zip

i have checked everywhere online and stackoverflow and could not find a match specific to this issue.
I am trying to extract a pdf file that is located in a zip file that is inside a zip file (nested zips).
Re-calling the method i am using to extract does not work nor does changing the whole program to accept Inputstreams instead of how i am doing it below.
The .pdf file inside the nested zip is just skipped at this stage
public static void main(String[] args)
{
try
{
//Paths
String basePath = "C:\\Users\\user\\Desktop\\Scan\\";
File lookupDir = new File(basePath + "Data\\");
String doneFolder = basePath + "DoneUnzipping\\";
File[] directoryListing = lookupDir.listFiles();
for (int i = 0; i < directoryListing.length; i++)
{
if (directoryListing[i].isFile()) //there's definately a file
{
//Save the current file's path
String pathOrigFile = directoryListing[i].getAbsolutePath();
Path origFileDone = Paths.get(pathOrigFile);
Path newFileDone = Paths.get(doneFolder + directoryListing[i].getName());
//unzip it
if(directoryListing[i].getName().toUpperCase().endsWith(ZIP_EXTENSION)) //ZIP files
{
unzip(directoryListing[i].getAbsolutePath(), DESTINATION_DIRECTORY + directoryListing[i].getName());
//move to the 'DoneUnzipping' folder
Files.move(origFileDone, newFileDone);
}
}
}
} catch (Exception e)
{
e.printStackTrace(System.out);
}
}
private static void unzip(String zipFilePath, String destDir)
{
//buffer for read and write data to file
byte[] buffer = new byte[BUFFER_SIZE];
try (ZipInputStream zis = new ZipInputStream(new FileInputStream(zipFilePath)))
{
FileInputStream fis = new FileInputStream(zipFilePath);
ZipEntry ze = zis.getNextEntry();
while(ze != null)
{
String fileName = ze.getName();
int index = fileName.lastIndexOf("/");
String newFileName = fileName.substring(index + 1);
File newFile = new File(destDir + File.separator + newFileName);
//Zips inside zips
if(fileName.toUpperCase().endsWith(ZIP_EXTENSION))
{
ZipInputStream innerZip = new ZipInputStream(zis);
ZipEntry innerEntry = null;
while((innerEntry = innerZip.getNextEntry()) != null)
{
System.out.println("The file: " + fileName);
if(fileName.toUpperCase().endsWith("PDF"))
{
FileOutputStream fos = new FileOutputStream(newFile);
int len;
while ((len = innerZip.read(buffer)) > 0)
{
fos.write(buffer, 0, len);
}
fos.close();
}
}
}
//close this ZipEntry
zis.closeEntry(); // java.io.IOException: Stream Closed
ze = zis.getNextEntry();
}
//close last ZipEntry
zis.close();
fis.close();
} catch (IOException e)
{
e.printStackTrace();
}
}

The solution to this is not as obvious as it seems. Despite writing a few zip utilities myself some time ago, getting zip entries from inside another zip file only seems obvious in retrospect
(and I also got the java.io.IOException: Stream Closed on my first attempt).
The Java classes for ZipFile and ZipInputStream really direct your thinking into using the file system, but it is not required.
The functions below will scan a parent-level zip file, and continue scanning until it finds an entry with a specified name. (Nearly) everything is done in-memory.
Naturally, this can be modified to use different search criteria, find multiple file types, etc. and take different actions, but this at least demonstrates the basic technique in question -- zip files inside of zip files -- no guarantees on other aspects of the code, and someone more savvy could most likely improve the style.
final static String ZIP_EXTENSION = ".zip";
public static byte[] getOnePDF() throws IOException
{
final File source = new File("/path/to/MegaData.zip");
final String nameToFind = "FindThisFile.pdf";
final ByteArrayOutputStream mem = new ByteArrayOutputStream();
try (final ZipInputStream in = new ZipInputStream(new BufferedInputStream(new FileInputStream(source))))
{
digIntoContents(in, nameToFind, mem);
}
// Save to disk, if you want
// copy(new ByteArrayInputStream(mem.toByteArray()), new FileOutputStream(new File("/path/to/output.pdf")));
// Otherwise, just return the binary data
return mem.toByteArray();
}
private static void digIntoContents(final ZipInputStream in, final String nameToFind, final ByteArrayOutputStream mem) throws IOException
{
ZipEntry entry;
while (null != (entry = in.getNextEntry()))
{
final String name = entry.getName();
// Found the file we are looking for
if (name.equals(nameToFind))
{
copy(in, mem);
return;
}
// Found another zip file
if (name.toUpperCase().endsWith(ZIP_EXTENSION.toUpperCase()))
{
digIntoContents(new ZipInputStream(new ByteArrayInputStream(getZipEntryFromMemory(in))), nameToFind, mem);
}
}
}
private static byte[] getZipEntryFromMemory(final ZipInputStream in) throws IOException
{
final ByteArrayOutputStream mem = new ByteArrayOutputStream();
copy(in, mem);
return mem.toByteArray();
}
// General purpose, reusable, utility function
// OK for binary data (bad for non-ASCII text, use Reader/Writer instead)
public static void copy(final InputStream from, final OutputStream to) throws IOException
{
final int bufferSize = 4096;
final byte[] buf = new byte[bufferSize];
int len;
while (0 < (len = from.read(buf)))
{
to.write(buf, 0, len);
}
to.flush();
}

Your question asks how to use java (by implication in windows) to extract a pdf from a zip inside another outer zip.
In many systems including windows it is a single line command that will depend on the location of source and target folders, however using the shortest example of current downloads folder it would be in a shell as simple as
tar -xf "german (2).zip" && tar -xf "german.zip" && german.pdf
to shell the command in windows see
How do I execute Windows commands in Java?
The default pdf viewer can open the result so Windows Edge or in my case SumatraPDF
There is generally no point in putting a pdf inside a zip because it cannot be run in there. So single nesting would be advisable if needed for download transportation.
There is no need to add a password to the zip because PDF uses its own password for opening. Thus unwise to add two levels of complexity. Keep it simple.
If you have multiple zips nested inside multiple zips with multiple pdfs in each then you have to be more specific by filtering names. However avoid that extra onion skin where possible.
\Downloads>tar -xf "german (2).zip" "both.zip" && tar -xf "both.zip" "English language.pdf"
You could complicate that by run in a memory or temp folder but it is reliable and simple to use the native file system so consider without Java its fastest to run
CD /D "C:/Users/user/Desktop/Scan/DoneUnzipping" && for %f in (..\Data\*.zip) do tar -xf "%f" "*.zip" && for %f in (*.zip) do tar -xf "%f" "*.pdf" && del "*.zip"
This will extract all inner zips into working folder then extract all PDFs and remove all the essential temporary zips. The source double zips will not be deleted simply touched.

The line that causes your problem looks to be auto-close block you have created when reading the inner zip:
try(ZipInputStream innerZip = new ZipInputStream(fis)) {
...
}
Several likely issues: firstly it is reading the wrong stream - fis not the existing zis.
Secondly, you shouldn't use try-with-resources for auto-close on innerZip as this implicitly calls innerZip.close() when exiting the block. If you view the source code of ZipInputStream via a good IDE you should see (eventually) that ZipInputStream extends InflaterInputStream which itself extends FilterInputStream. A call to innerZip.close() will close the underlying outer stream zis (fis in your case) hence stream is closed when you resume the next entry of the outer zip.
Therefore remove the try() block and add use of zis:
ZipInputStream innerZip = new ZipInputStream(zis);
Use try-catch block only for the outermost file handling:
try (ZipInputStream zis = new ZipInputStream(new FileInputStream(zipFilePath))) {
ZipEntry ze = zis.getNextEntry();
...
}
Thirdly, you appear to be copying the wrong stream when extracting a PDF - use innerZip not outer zis. The code will never extract PDF as these 2 lines can never be true at the same time because a file ending ZIP will never end PDF too:
if(fileName.toUpperCase().endsWith(ZIP_EXTENSION)) {
...
// You want innerEntry.getName() here
if(fileName.toUpperCase().endsWith("PDF"))
You should be able to switch to one line Files.copy and make use of the PDF filename not zip filename:
if(innerEntry.getName().toUpperCase().endsWith("PDF")) {
Path newFile = Paths.get(destDir + '-'+innerEntry.getName().replace("/", "-"));
System.out.println("Files.copy to " + newFile);
Files.copy(innerZip, newFile);
}

Java program ignoring all the files inside the zip file [duplicate]

This question already has answers here:
How to unzip files recursively in Java?
(10 answers)
Closed last month.
I have program when I give a zip folder path via console. It will go through each item inside that folder (every child item, children of child, etc..). But if it encounters a zip folder it will ignore everything inside the zip folder, I need to read everything including files inside zip folders.
Here is the method that goes through each item:
public static String[] getLogBuffers(String path) throws IOException//path is given via console
{
String zipFileName = path;
String destDirectory = path;
BufferedInputStream errorLogBuffer = null;
BufferedInputStream windowLogBuffer = null;
String strErrorLogFileContents="";
String strWindowLogFileContents="";
String[] errorString=new String[2];
byte[] buffer = new byte[1024];
ZipInputStream zis = new ZipInputStream(new FileInputStream(zipFileName));
ZipEntry zipEntry = zis.getNextEntry();
while (zipEntry != null)
{
String filePath = destDirectory + "/" + zipEntry.getName();
System.out.println("unzipping" + filePath);
if (!zipEntry.isDirectory())
{
if (zipEntry.getName().endsWith("errorlog.txt"))
{
ZipFile zipFile = new ZipFile(path);
InputStream errorStream = zipFile.getInputStream(zipEntry);
BufferedInputStream bufferedInputStream=new BufferedInputStream(errorStream);
byte[] contents = new byte[1024];
System.out.println("ERRORLOG NAME"+zipEntry.getName());
int bytesRead = 0;
while((bytesRead = bufferedInputStream.read(contents)) != -1) {
strErrorLogFileContents += new String(contents, 0, bytesRead);
}
}
if (zipEntry.getName().endsWith("windowlog.txt"))
{ ZipFile zipFile = new ZipFile(path);
InputStream windowStream = zipFile.getInputStream(zipEntry);
BufferedInputStream bufferedInputStream=new BufferedInputStream(windowStream);
byte[] contents = new byte[1024];
System.out.println("WINDOWLOG NAME"+zipEntry.getName());
int bytesRead = 0;
while((bytesRead = bufferedInputStream.read(contents)) != -1) {
strWindowLogFileContents += new String(contents, 0, bytesRead);
}
}
}
zis.closeEntry();
zipEntry = zis.getNextEntry();
}
errorString[0]=strErrorLogFileContents;
errorString[1]=strWindowLogFileContents;
zis.closeEntry();
zis.close();
System.out.println("Buffers ready");
return errorString;
}
Items accessed inside the parent zip folder (my console output):
unzippingC:logFolders/logX3.zip/logX3/
unzippingC:logFolders/logX3.zip/logX3/Anan/
unzippingC:logFolders/logX3.zip/logX3/Anan/errorreports/
unzippingC:logFolders/logX3.zip/logX3/Anan/errorreports/2021-11-23_103518.zip
unzippingC:logFolders/logX3.zip/logX3/Anan/errorreports/errorlog.txt
unzippingC:logX3.zip/logX3/Anan/errorreports/version.txt
unzippingC:logFolders/logX3.zip/logX3/Anan/errorreports/windowlog.txt
As you can see the program only go until 2021-11-23_103518.zip and goes in another path after that but 2021-11-23_103518.zip has children items(files) that I need to access
appreciate any help, thanks

A zip file is not a folder. Although Windows treats a zip file as if it’s a folder,* it is not a folder. A .zip file is a single file with an internal table of entries, each containing compressed data.
Each inner .zip file you read requires a new ZipFile or ZipInputStream. There is no way around that.
You should not create new ZipFile instances to read the same .zip file’s entries. You only need one ZipFile object. You can go through its entries with its entries() method, and you can read each entry with the ZipFile’s getInputStream method.
(I wouldn’t be surprised if using multiple objects to read the same zip file were to run into file locking problems on Windows.)
try (ZipFile zipFile = new ZipFile(path))
{
Enumeration<? extends ZipEntry> entries = zipFile.entries();
while (entries.hasMoreElements())
{
ZipEntry zipEntry = entries.nextElement();
if (zipEntry.getName().endsWith("errorlog.txt"))
{
try (InputStream errorStream = zipFile.getInputStream(zipEntry))
{
// ...
}
}
}
}
Notice that no other ZipFile or ZipInputStream objects are created. Only zipFile reads and traverses the file. Also notice the use of a try-with-resources statement to implicitly close the ZipFile and the InputStream.
You should not use += to build a String. Doing so creates a lot of intermediate String objects which will have to be garbage collected, which can hurt your program’s performance. You should wrap each zip entry’s InputStream in an InputStreamReader, then use that Reader’s transferTo method to append to a single StringWriter that holds your combined log.
String strErrorLogFileContents = new StringWriter();
String strWindowLogFileContents = new StringWriter();
try (ZipFile zipFile = new ZipFile(path))
{
Enumeration<? extends ZipEntry> entries = zipFile.entries();
while (entries.hasMoreElements())
{
ZipEntry zipEntry = entries.nextElement();
if (zipEntry.getName().endsWith("errorlog.txt"))
{
try (Reader entryReader = new InputStreamReader(
zipFile.getInputStream(zipEntry),
StandardCharsets.UTF_8))
{
entryReader.transferTo(strErrorLogFileContents);
}
}
}
}
Notice the use of StandardCharsets.UTF_8. It is almost never correct to create a String from bytes without specifying the Charset. If you don’t provide the Charset, Java will use the system’s default Charset, which means your program will behave differently in Windows than it will on other operating systems.
If you are stuck with Java 8, you won’t have the transferTo method of Reader, so you will have to do the work yourself:
if (zipEntry.getName().endsWith("errorlog.txt"))
{
try (Reader entryReader = new BufferedReader(
new InputStreamReader(
zipFile.getInputStream(zipEntry),
StandardCharsets.UTF_8)))
{
int c;
while ((c = entryReader.read()) >= 0)
{
strErrorLogFileContents.write(c);
}
}
}
The use of BufferedReader means you don’t need to create your own array and implement bulk reads yourself. BufferedReader already does that for you.
As mentioned above, a zip entry which is itself an inner zip file requires a brand new ZipFile or ZipInputStream object to read it. I recommend copying the entry to a temporary file, since reading from a ZipInputStream made from another ZipInputStream is known to be slow, then deleting the temporary file after you’re done reading it.
try (ZipFile zipFile = new ZipFile(path))
{
Enumeration<? extends ZipEntry> entries = zipFile.entries();
while (entries.hasMoreElements())
{
ZipEntry zipEntry = entries.nextElement();
if (zipEntry.getName().endsWith(".zip"))
{
Path tempZipFile = Files.createTempFile(null, ".zip");
try (InputStream errorStream = zipFile.getInputStream(zipEntry))
{
Files.copy(errorStream, tempZipFile,
StandardCopyOption.REPLACE_EXISTING);
}
String[] logsFromZip = getLogBuffers(tempZipFile.toString());
strErrorLogFileContents.write(logsFromZip[0]);
strWindowLogFileContents.write(logsFromZip[1]);
Files.delete(tempZipFile);
}
}
}
Finally, consider creating a meaningful class for your return value. An array of Strings is difficult to understand. A caller won’t know that it always contains exactly two elements and won’t know what those two elements are. A custom return type would be pretty short:
public class Logs {
private final String errorLog;
private final String windowLog;
public Logs(String errorLog,
String windowLog)
{
this.errorLog = errorLog;
this.windowLog = windowLog;
}
public String getErrorLog()
{
return errorLog;
}
public String getWindowLog()
{
return windowLog;
}
}
As of Java 16, you can use a record to make the declaration much shorter:
public record Logs(String errorLog,
String windowLog)
{ }
Whether you use a record or write out the class, you can use it as a return type in your method:
public static Logs getLogBuffers(String path) throws IOException
{
// ...
return new Logs(
strErrorLogFileContents.toString(),
strWindowLogFileContents.toString());
}
* The Windows explorer shell’s practice of treating zip files as folders is a pretty bad user interface. I know I’m not the only one who thinks so. It often ends up making things more difficult for users instead of easier.

How to unzip file with sub-directories in android?

When i was unzip file.it's make file name like Movies\Hollywood\spider-Man.
Actually Movies is a Folder,Hollywood is a Folder in Movies and spider-Man is file in Hollywood.

If Movies\Hollywood\spider-Man is a file while creating the zip it should be extracted as file, no matters whether it has extension or not (like *.mp4, *.flv)
You can rely on java APIs under namespace java.util.zip, the documentation link is here
Written some code which extracts only zip files, it should extract the file entry as file (no gzip, rar is supported).
private boolean extractFolder(File destination, File zipFile) throws ZipException, IOException
{
int BUFFER = 8192;
File file = zipFile;
//This can throw ZipException if file is not valid zip archive
ZipFile zip = new ZipFile(file);
String newPath = destination.getAbsolutePath() + File.separator + FilenameUtils.removeExtension(zipFile.getName());
//Create destination directory
new File(newPath).mkdir();
Enumeration zipFileEntries = zip.entries();
//Iterate overall zip file entries
while (zipFileEntries.hasMoreElements())
{
ZipEntry entry = (ZipEntry) zipFileEntries.nextElement();
String currentEntry = entry.getName();
File destFile = new File(newPath, currentEntry);
File destinationParent = destFile.getParentFile();
//If entry is directory create sub directory on file system
destinationParent.mkdirs();
if (!entry.isDirectory())
{
//Copy over data into destination file
BufferedInputStream is = new BufferedInputStream(zip
.getInputStream(entry));
int currentByte;
byte data[] = new byte[BUFFER];
//orthodox way of copying file data using streams
FileOutputStream fos = new FileOutputStream(destFile);
BufferedOutputStream dest = new BufferedOutputStream(fos, BUFFER);
while ((currentByte = is.read(data, 0, BUFFER)) != -1) {
dest.write(data, 0, currentByte);
}
dest.flush();
dest.close();
is.close();
}
}
return true;//some error codes etc.
}
The routine does not perform any exception handling, please catch the ZipException and IOException inside driver code.

Zipping Files using util.zip No directory

I have the following situation:
I am able to zip my files with the following method:
public boolean generateZip(){
byte[] application = new byte[100000];
ByteArrayOutputStream baos = new ByteArrayOutputStream();
// These are the files to include in the ZIP file
String[] filenames = new String[]{"/subdirectory/index.html", "/subdirectory/webindex.html"};
// Create a buffer for reading the files
try {
// Create the ZIP file
ZipOutputStream out = new ZipOutputStream(baos);
// Compress the files
for (int i=0; i<filenames.length; i++) {
byte[] filedata = VirtualFile.fromRelativePath(filenames[i]).content();
ByteArrayInputStream in = new ByteArrayInputStream(filedata);
// Add ZIP entry to output stream.
out.putNextEntry(new ZipEntry(filenames[i]));
// Transfer bytes from the file to the ZIP file
int len;
while ((len = in.read(application)) > 0) {
out.write(application, 0, len);
}
// Complete the entry
out.closeEntry();
in.close();
}
// Complete the ZIP file
out.close();
} catch (IOException e) {
System.out.println("There was an error generating ZIP.");
e.printStackTrace();
}
downloadzip(baos.toByteArray());
}
This works perfectly and I can download the xy.zip which contains the following directory and file structure:
subdirectory/
----index.html
----webindex.html
My aim is to completely leave out the subdirectory and the zip should only contain the two files. Is there any way to achieve this?
(I am using Java on Google App Engine).
Thanks in advance

If you are sure the files contained in the filenames array are unique if you leave out the directory, change your line for constructing ZipEntrys:
String zipEntryName = new File(filenames[i]).getName();
out.putNextEntry(new ZipEntry(zipEntryName));
This uses java.io.File#getName()

You can use Apache Commons io to list all your files, then read them to an InputStream
Replace the line below
String[] filenames = new String[]{"/subdirectory/index.html", "/subdirectory/webindex.html"}
with the following
Collection<File> files = FileUtils.listFiles(new File("/subdirectory"), new String[]{"html"}, true);
for (File file : files)
{
FileInputStream fileStream = new FileInputStream(file);
byte[] filedata = IOUtils.toByteArray(fileStream);
//From here you can proceed with your zipping.
}
Let me know if you have issues.

You could use the isDirectory() method on VirtualFile

FileNotFoundException when trying to unzip an archive with java.util.zip.ZipFile

I have a silly problem i haven't been able to figure out. Can anyone help me?
My Code is as:
String zipname = "C:/1100.zip";
String output = "C:/1100";
BufferedInputStream bis = null;
BufferedOutputStream bos = null;
try {
ZipFile zipFile = new ZipFile(zipname);
Enumeration<?> enumeration = zipFile.entries();
while (enumeration.hasMoreElements()) {
ZipEntry zipEntry = (ZipEntry) enumeration.nextElement();
System.out.println("Unzipping: " + zipEntry.getName());
bis = new BufferedInputStream(zipFile.getInputStream(zipEntry));
int size;
byte[] buffer = new byte[2048];
It doesn't create a folder but debugging shows all the contents being generated.
In Order to create a folder i used the code
if(!output.exists()){ output.mkdir();} // here i get an error saying filenotfoundexception
bos = new BufferedOutputStream(new FileOutputStream(new File(outPut)));
while ((size = bis.read(buffer)) != -1) {
bos.write(buffer, 0, size);
}
}
} catch (Exception ex) {
ex.printStackTrace();
} finally {
bos.flush();
bos.close();
bis.close();
}
My zip file contains images: a.jpg b.jpg... and in the same hierarchy, I have abc.xml.
I need to extract the content as is in the zip file.
Any helps here.

There are a few problems with your code: Where is outPut declared? output is not a file but a string, so exists() and mkdir() do not exist. Start by declaring output like:
File output = new File("C:/1100");
Furthermore, outPut (with big P) is not declared. It be something like output + File.seprator + zipEntry.getName().
bos = new BufferedOutputStream(new FileOutputStream(output + File.seprator + zipEntry.getName()));
Note that you don't need to pass a File to FileOutputStream, as constructors show in the documentation.
At this point, your code should work if your Zip file does not contain directory. However, when opening the output stream, if zipEntry.getName() has a directory component (for instance somedir/filename.txt), opening the stream will result in a FileNotFoundException, as the parent directory of the file you try to create does not exist. If you want to be able to handle such zip files, you will find your answer in: How to unzip files recursively in Java?