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

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What is a good Java library to zip unzip files?

A very nice project is TrueZip.

Can Java open Zip files?

To unzip a zip file, we need to read the zip file with ZipInputStream and then read all the ZipEntry one by one. Then use FileOutputStream to write them to file system. We also need to create the output directory if it doesn't exists and any nested directories present in the zip file.

How can I read the content of a zip file without unzipping it in Java?

Methods. getComment(): String – returns the zip file comment, or null if none. getEntry(String name): ZipEntry – returns the zip file entry for the specified name, or null if not found. getInputStream(ZipEntry entry) : InputStream – Returns an input stream for reading the contents of the specified zip file entry.


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>

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.


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();
        }
    }
}

Another option that you can check out is zt-zip available from Maven central and project page at https://github.com/zeroturnaround/zt-zip

It has the standard packing and unpacking functionality (on streams and on filesystem) + lots of helper methods to test for files in an archive or add/remove entries.