What is a good Java library to zip/unzip files? [closed]

Solution 1:

I know its late and there are lots of answers but this zip4j is one of the best libraries for zipping I have used. Its simple (no boiler code) and can easily handle password protected files.

import net.lingala.zip4j.exception.ZipException;
import net.lingala.zip4j.core.ZipFile;


public static void unzip(){
    String source = "some/compressed/file.zip";
    String destination = "some/destination/folder";
    String password = "password";

    try {
         ZipFile zipFile = new ZipFile(source);
         if (zipFile.isEncrypted()) {
            zipFile.setPassword(password);
         }
         zipFile.extractAll(destination);
    } catch (ZipException e) {
        e.printStackTrace();
    }
}

The Maven dependency is:

<dependency>
    <groupId>net.lingala.zip4j</groupId>
    <artifactId>zip4j</artifactId>
    <version>1.3.2</version>
</dependency>

Solution 2:

In Java 8, with Apache Commons-IO's IOUtils you can do this:

try (java.util.zip.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 {
        entryDestination.getParentFile().mkdirs();
        try (InputStream in = zipFile.getInputStream(entry);
             OutputStream out = new FileOutputStream(entryDestination)) {
            IOUtils.copy(in, out);
        }
    }
  }
}

It's still some boilerplate code, but it has only 1 non-exotic dependency: Commons-IO

In Java 11 and higher, better options might be available, see ZhekaKozlov's comment.

Solution 3:

Extract zip file and all its subfolders, using only the JDK:

private void extractFolder(String zipFile,String extractFolder) 
{
    try
    {
        int BUFFER = 2048;
        File file = new File(zipFile);

        ZipFile zip = new ZipFile(file);
        String newPath = extractFolder;

        new File(newPath).mkdir();
        Enumeration zipFileEntries = zip.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(newPath, currentEntry);
            //destFile = new File(newPath, destFile.getName());
            File destinationParent = destFile.getParentFile();

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

            if (!entry.isDirectory())
            {
                BufferedInputStream is = new BufferedInputStream(zip
                .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 (Exception e) 
    {
        Log("ERROR: "+e.getMessage());
    }

}

Zip files and all its subfolders:

 private void addFolderToZip(File folder, ZipOutputStream zip, String baseName) throws IOException {
    File[] files = folder.listFiles();
    for (File file : files) {
        if (file.isDirectory()) {
            addFolderToZip(file, zip, baseName);
        } else {
            String name = file.getAbsolutePath().substring(baseName.length());
            ZipEntry zipEntry = new ZipEntry(name);
            zip.putNextEntry(zipEntry);
            IOUtils.copy(new FileInputStream(file), zip);
            zip.closeEntry();
        }
    }
}