copying folder and all of its contents

[Mark Hughes]

Hey Guys,
I came across code to copy a file, simple enough

 
copy("config/file.xml", "config2/file.xml.");
 

but does anyone know a similar method that would work for a whole folder and the folder contents?

Regards

Mark

[Stan James]

It's pretty easy to write. Look into File.list and try something like

private void copy( source folder, target folder )
{
   File[] = list files in a folder
   for each file
      call your existing copy method for one file
   next
}

Now if your folder contains subfolders, you'll have to add a bit

private void copyFolder( source folder, target folder )
{
   File[] = list files in a folder
   for each file
      if file is a folder
         make target subfolder in target folder
         call copyFolder( source subfolder, target subfolder )
      else
         call your existing copy method for one file
   next
}

Are you comfortable with that kind of recursion? Is that enough to go on?
[ November 09, 2006: Message edited by: Stan James ]

[Mark Hughes]

sorry guys i forgot to put in the copy method,

but anyway i came across this code for copying a directory which works great

  public void copyDirectory(File sourceLocation , File targetLocation)
    throws IOException {
        
        if (sourceLocation.isDirectory()) {
            if (!targetLocation.exists()) {
                targetLocation.mkdir();
            }
            
            String[] children = sourceLocation.list();
            for (int i=0; i<children.length; i++) {
                copyDirectory(new File(sourceLocation, children[i]),
                        new File(targetLocation, children[i]));
            }
        } else {
            
            InputStream in = new FileInputStream(sourceLocation);
            OutputStream out = new FileOutputStream(targetLocation);
            
            // Copy the bits from instream to outstream
            byte[] buf = new byte[1024];
            int len;
            while ((len = in.read(buf)) > 0) {
                out.write(buf, 0, len);
            }
            in.close();
            out.close();
        }
    }

thanks

mark

[Mark Hughes]

thanks stan,

i like the way you broke it down, makes alot of sense seeing it in that form rather than a bunch of code.

Cheers mark

[Stan James]

I frequently scribble that kind of psuedo code out to start a problem. What's fun is to translate to code line per line. I haven't compiled or checked this but consider ...

private void copyFolder( File source, File target )
{
   Files[] = source.list();
   for ( File file : files )
   {
      if file.isDirectory()
      {
         File newTarget = makeSubdirectory( file );
         copyFolder( file, newTarget );
      }
      else
         copyFile( file, target );
   }
}

That's pretty near one-to-one with the sketch from before. Your logic is actually better because it allows the first "source" argument to be a file or directory. For fun try to make it this expressive and keep that feature.

[Ilja Preuss]

Why reinvent the wheel? I'd simply use http://jakarta.apache.org/commons/io/api-release/org/apache/commons/io/FileUtils.html