Compress directory into a zipfile with Commons IO

Question

I am a beginner at programming with Java and am currently writing an application which must be able to compress and decompress .zip files. I can use the following code to decompress a zipfile in Java using the built-in Java zip functionality as well as the Apache Commons IO library:

public static void decompressZipfile(String file, String outputDir) throws IOException {
    if (!new File(outputDir).exists()) {
        new File(outputDir).mkdirs();
    }
    ZipFile zipFile = new ZipFile(file);
    Enumeration<? extends ZipEntry> entries = zipFile.entries();
    while (entries.hasMoreElements()) {
        ZipEntry entry = entries.nextElement();
        File entryDestination = new File(outputDir, entry.getName());
        if (entry.isDirectory()) {
            entryDestination.mkdirs();
        } else {
            InputStream in = zipFile.getInputStream(entry);
            OutputStream out = new FileOutputStream(entryDestination);
            IOUtils.copy(in, out);
            IOUtils.closeQuietly(in);
            IOUtils.closeQuietly(out);
        }
    }
}

How would I go about creating a zipfile from a directory using no external libraries other than what I am already using? (Java standard libraries and Commons IO)

Answer 1

The following method(s) seem to successfully compress a directory recursively:

public static void compressZipfile(String sourceDir, String outputFile) throws IOException, FileNotFoundException {
    ZipOutputStream zipFile = new ZipOutputStream(new FileOutputStream(outputFile));
    compressDirectoryToZipfile(sourceDir, sourceDir, zipFile);
    IOUtils.closeQuietly(zipFile);
}

private static void compressDirectoryToZipfile(String rootDir, String sourceDir, ZipOutputStream out) throws IOException, FileNotFoundException {
    for (File file : new File(sourceDir).listFiles()) {
        if (file.isDirectory()) {
            compressDirectoryToZipfile(rootDir, sourceDir + File.separator + file.getName(), out);
        } else {
            ZipEntry entry = new ZipEntry(sourceDir.replace(rootDir, "") + file.getName());
            out.putNextEntry(entry);

            FileInputStream in = new FileInputStream(sourceDir + file.getName());
            IOUtils.copy(in, out);
            IOUtils.closeQuietly(in);
        }
    }
}

As seen in my compression code snippet, I'm using IOUtils.copy() to handle stream data transfer.