Hello world example on VFS: create a zip file from scratch

apache-commons-vfs, java, zip

Solution

The answer to my need is the following code snippet:

// Create access to zip.
FileSystemManager fsManager = VFS.getManager();
FileObject zipFile = fsManager.resolveFile("file:/path/to/the/file.zip");
zipFile.createFile();
ZipOutputStream zos = new ZipOutputStream(zipFile.getContent().getOutputStream());

// add entry/-ies.
ZipEntry zipEntry = new ZipEntry("name_inside_zip");
FileObject entryFile = fsManager.resolveFile("file:/path/to/the/sourcefile.txt");
InputStream is = entryFile.getContent().getInputStream();

// Write to zip.
byte[] buf = new byte[1024];
zos.putNextEntry(zipEntry);
for (int readNum; (readNum = is.read(buf)) != -1;) {
   zos.write(buf, 0, readNum);
}

After this you need to close the streams and it works!

Problem

I would like to create a zip file with Commons VFS2 library. I know how to copy a file when using `file` prefix but for `zip` files write and read are not implemented. `fileSystemManager.resolveFile("path comes here")`-method fails when I try path `zip:/some/file.zip` when file.zip is an non-existing zip-file. I can resolve an existing file but non-existing new file fails. So how to create that new zip file then? I cannot use createFile() because it is not supported and I cannot create the FileObject before this is to be called. The normal way is to create FileObject with that resolveFile and then call createFile for the object.

Original source