zip files portability on win and mac

[gianpi]

Hi,

I'm currently developing an application which, among other things,
should zip some folders with all their content (therefore, also
subfolders).
Browsing I found and slightly adapted the following code:

public class ZipUtil {
private ZipOutputStream cpZipOutputStream = null;
private String strSource = "";
private String strTarget = "";
private String strSubstring = "";

public void ZipDirectory (String dir2zip, String destFile){
strSource = dir2zip;
strTarget = destFile;
zip();
}

private void zip(){
try{
File cpFile = new File (strSource);
if (!cpFile.isFile() && !cpFile.isDirectory() ) {
System.out.println("\nSource file/directory Not Found!");
return;
}
if (cpFile.isDirectory()) {
strSubstring = strSource;
} else {
strSubstring = "";
}
FileOutputStream fos = new FileOutputStream(strTarget);
cpZipOutputStream = new ZipOutputStream(fos);
cpZipOutputStream.setLevel(9);
zipFiles(cpFile);
cpZipOutputStream.finish();
cpZipOutputStream.close();
fos.close();
}catch (Exception e){
e.printStackTrace();
}
}

private void zipFiles(File cpFile) {
if (cpFile.isDirectory()) {
File [] fList = cpFile.listFiles() ;
for (int i=0; i< fList.length; i++){
zipFiles(fList) ;
}
} else {
try {
String strAbsPath = cpFile.getAbsolutePath();
String strZipEntryName ="";
if (!strSubstring.equals("") ){

strZipEntryName = strAbsPath.substring(
strSource.length()+1, strAbsPath.length());

} else {
strZipEntryName = cpFile.getName();
}
byte[] b = new byte[ (int)(cpFile.length()) ];
FileInputStream cpFileInputStream =
new FileInputStream (cpFile) ;
cpFileInputStream.read(b, 0, (int)cpFile.length());
ZipEntry cpZipEntry = new ZipEntry(strZipEntryName);
cpZipOutputStream.putNextEntry(cpZipEntry );
cpZipOutputStream.write(b, 0, (int)cpFile.length());
cpZipOutputStream.closeEntry() ;
cpFileInputStream.close();
} catch (Exception e) {
e.printStackTrace();
}
}
}
}

The problem is that when I run this on Windows, the following line:

strZipEntryName = strAbsPath.substring(strSource.length()+1,
strAbsPath.length());

uses the backslash as File.separator. So the zip file contains all the
folders and subfolders when I extract the zip file on Windows.
On the other hand, if I try to extract on a Mac, it will consider the
backslash as part of the filename.

e.g.
folder\foo.bar

On Windows it's a folder with a foo.bar file inside.
On Mac, it is a file named "folder\foo".

Am I wrong somewhere, or is there any workaround for this problem?
I'd like my zip files to be as portable as my application

Thanks in advance for your answer!

gianpi

 

[Joshua Cranmer]

Typically, errors should be using System.err, not System.out

e.g.
folder\foo.bar

On Windows it's a folder with a foo.bar file inside.
On Mac, it is a file named "folder\foo".

I take it that this is view from inside the zip file.

Am I wrong somewhere, or is there any workaround for this problem?

I'm rusty on my ZIP file specification, but I believe that the file
separator is unambiguously "\", so there are two solutions:

1. Do a .replaceAll(File.separator, "\\") on the path name before you
put it in, or
2. Slightly refactor your code:

zip() {
if file is a directory
zipDir(file,"");
else
zipFile(file,"");
}

zipDir(File dir, String path) {
for all files
if file is directory, zipDir(file,path+dir.name())
else zipFile(file,path)
}

zipFile(File dir, String path) {
add to zip file
}

However, your code might run into problems with symlinked recursive
directories!

 

[rossum]

The problem is that when I run this on Windows, the following line:

strZipEntryName = strAbsPath.substring(strSource.length()+1,
strAbsPath.length());

uses the backslash as File.separator. So the zip file contains all the
folders and subfolders when I extract the zip file on Windows.
On the other hand, if I try to extract on a Mac, it will consider the
backslash as part of the filename.

e.g.
folder\foo.bar

On Windows it's a folder with a foo.bar file inside.
On Mac, it is a file named "folder\foo".

Am I wrong somewhere, or is there any workaround for this problem?
I'd like my zip files to be as portable as my application

Thanks in advance for your answer!

gianpi

Have you had a look at File.pathSeparator, File.pathSeparatorChar,
File.separator and File.separatorChar ?

One or other of those should be able to help.

rossum

 

[Roedy Green]

The problem is that when I run this on Windows, the following line:

strZipEntryName = strAbsPath.substring(strSource.length()+1,
strAbsPath.length())

When you examine the file with WinZip you will see \, but if you look
with a hex viewer, you will see /. You may well be ok.