How to unzip files recursively in Java?

Question

I have zip file which contains some other zip files.

For example, the mail file is abc.zip and it contains xyz.zip, class1.java

Answer 1

Here's some untested code base on some old code I had that unzipped files.

public void doUnzip(String inputZip, String destinationDirectory)
        throws IOException {
    int BUFFER = 2048;
    List zipFiles = new ArrayList();
    File sourceZipFile = new File(inputZip);
    File unzipDestinationDirectory = new File(destinationDirectory);
    unzipDestinationDirectory.mkdir();

    ZipFile zipFile;
    // Open Zip file for reading
    zipFile = new ZipFile(sourceZipFile, ZipFile.OPEN_READ);

    // Create an enumeration of the entries in the zip file
    Enumeration zipFileEntries = zipFile.entries();

    // Process each entry
    while (zipFileEntries.hasMoreElements()) {
        // grab a zip file entry
        ZipEntry entry = (ZipEntry) zipFileEntries.nextElement();

        String currentEntry = entry.getName();

        File destFile = new File(unzipDestinationDirectory, currentEntry);
        destFile = new File(unzipDestinationDirectory, destFile.getName());

        if (currentEntry.endsWith(".zip")) {
            zipFiles.add(destFile.getAbsolutePath());
        }

        // grab file's parent directory structure
        File destinationParent = destFile.getParentFile();

        // create the parent directory structure if needed
        destinationParent.mkdirs();

        try {
            // extract file if not a directory
            if (!entry.isDirectory()) {
                BufferedInputStream is =
                        new BufferedInputStream(zipFile.getInputStream(entry));
                int currentByte;
                // establish buffer for writing file
                byte data[] = new byte[BUFFER];

                // write the current file to disk
                FileOutputStream fos = new FileOutputStream(destFile);
                BufferedOutputStream dest =
                        new BufferedOutputStream(fos, BUFFER);

                // read and write until last byte is encountered
                while ((currentByte = is.read(data, 0, BUFFER)) != -1) {
                    dest.write(data, 0, currentByte);
                }
                dest.flush();
                dest.close();
                is.close();
            }
        } catch (IOException ioe) {
            ioe.printStackTrace();
        }
    }
    zipFile.close();

    for (Iterator iter = zipFiles.iterator(); iter.hasNext();) {
        String zipName = (String)iter.next();
        doUnzip(
            zipName,
            destinationDirectory +
                File.separatorChar +
                zipName.substring(0,zipName.lastIndexOf(".zip"))
        );
    }

}