How to unzip a zip file which contains another zip file?

[Ong CherYee]

I would like to unzip a zip file which contains 2 text files and another zip file inside it.

For example, the zip file to unzip is called "Books.zip" and it contains 2 text files and another zip file called "Price.zip".

I googled for the unzipping code commonly found on the net and used it. But the problem is that the code can only unzip the 2 text files. It seems unable to retrieve the contents inside the "Price.zip" folder.

The code used is shown below:

   
public void UnZip(String sourceZipFile,String destFilePath)
{
try
{
int i;
ZipFile zf = new ZipFile(sourceZipFile);
Enumeration nameentry = zf.entries();
Enumeration zipfileentry = zf.entries();
 
for(i = 0;i < zf.size();i++)
{
String zipEntryName = ((ZipEntry)(nameentry.nextElement())).getName();
ZipEntry zipentry = (ZipEntry)zipfileentry.nextElement();
InputStream in = zf.getInputStream(zipentry);
String outFileName = destFilePath + "
" + zipEntryName;
OutputStream out = new BufferedOutputStream(new FileOutputStream(outFileName));
long uncompressedFileSize = zipentry.getSize();
byte[] buf = new byte[(int)uncompressedFileSize|http://forum.java.sun.com/];
int len;
while((len = in.read(buf)) >= 0)
out.write(buf,0,len);
 
in.close();
out.close();
}
 
zf.close();
 
}catch(IOException e)
{
System.out.println("Error unzipping file");
}
}

How do I unzip and retrieve all the contents of a zip file which contains another zip file?

[Ulf Dittmer]

For unzipping it doesn't matter what type the files are; they're just treated as bytes anyway. The process doesn't work recursively, though. After you've unzipped Books.zip, you'll need to re-run this code with Price.zip.

[Rob Spoor]

ZipEntry zipentry = (ZipEntry)zipfileentry.nextElement();
InputStream in = zf.getInputStream(zipentry);
ZipInputStream zis = new ZipInputStream(in);
ZipEntry subentry;
while ((subentry = zis.getNextEntry()) != null)
{
    // copy EVERYTHING from zis to wherever you want it
    zis.closeEntry();
}

That should allow you to unzip the second file without extracting it. I'm a bit lazy regarding the copying here, but basically reading from a ZipInputStream reads everything for the current entry. You need to close that entry and go the next entry and copy everything again, until your done.