How to zip files and folders in Java?

Question

Please have a look at the below code.

public void startCompress(String path,String fileName,String outputLocation,int compressType,int filSize) throws Exception
    {        
        System.out.println("Input Location: "+path);
        System.out.println("Output Location: "+outputLocation);   

            System.out.println(compressType);
            byte[] bs=new byte[filSize];
            System.out.println(filSize);

            FileOutputStream fos=new FileOutputStream(outputLocation+"/test.zip");

            System.out.println(fos.toString());
            ZipOutputStream zos=new ZipOutputStream(fos);

            ZipEntry ze = new ZipEntry(fileName);

            zos.putNextEntry(ze);

            FileInputStream inputStream=new FileInputStream(path);

            int len;
            while((len=inputStream.read(bs))>0){
                zos.write(bs, 0, len);                
            }
            inputStream.close();
            zos.closeEntry();
            zos.close();

    }

In above code, we compress a file using java.util.zip package. But we have an issue. That is, if we select multiple files then only one file is being compressed. If we select a folder, the compression simply won't work.

How can I fix this to compress either a file, files, folder, folders, or even nested folders? Java zip package does support .zip, .tar, .tarGz and tarZ. So the solution should not be something which is limited to .zip extension as well.

Answer 1

The zip libraries for java cannot be used to compress folders in simpler way like - compress this folder.

You need to do the test if the input is folder or file by yourself. If it is a file - add it to the zip. If it is a folder - iterate the folder and add each file to the zip. For the subfolders to the same. To add more than one file to the Zip you need to create ZipEntry for each file.

You can try this code which works for me:

public static void zip(File directory, File zipfile) throws IOException {
    URI base = directory.toURI();
    Deque<File> queue = new LinkedList<File>();
    queue.push(directory);
    OutputStream out = new FileOutputStream(zipfile);
    Closeable res = out;
    try {
        ZipOutputStream zout = new ZipOutputStream(out);
        res = zout;
        while (!queue.isEmpty()) {
            directory = queue.pop();
            for (File kid : directory.listFiles()) {
                String name = base.relativize(kid.toURI()).getPath();
                if (kid.isDirectory()) {
                    queue.push(kid);
                    name = name.endsWith("/") ? name : name + "/";
                    zout.putNextEntry(new ZipEntry(name));
                } else {
                    zout.putNextEntry(new ZipEntry(name));
                    copy(kid, zout);
                    zout.closeEntry();
                }
            }
        }
    } finally {
        res.close();
    }
}