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In my previous post here I have explain about the recursive file and folder copy with C#. This time I want to do the same with Java. You can easily copy files and folders by using the copy(Path, Path, CopyOption) method. However, files inside a folder are not copied and you can find the new folder empty even the destination folder has some.

In the following method I did not use such APIs, instead read byte streams from the source and copied into the destination when you want to copy files and create folders when you want copy folders from source to destination.

private void recursiveCopy(File fSource, File fDest) {
     try {
          if (fSource.isDirectory()) {
          // A simple validation, if the destination is not exist then create it
               if (!fDest.exists()) {
                    fDest.mkdirs();
               }

               // Create list of files and directories on the current source
               // Note: with the recursion 'fSource' changed accordingly
               String[] fList = fSource.list();

               for (int index = 0; index < fList.length; index++) {
                    File dest = new File(fDest, fList[index]);
                    File source = new File(fSource, fList[index]);

                    // Recursion call take place here
                    recursiveCopy(source, dest);
               }
          }
          else {
               // Found a file. Copy it into the destination, which is already created in 'if' condition above

               // Open a file for read and write (copy)
               FileInputStream fInStream = new FileInputStream(fSource);
               FileOutputStream fOutStream = new FileOutputStream(fDest);

               // Read 2K at a time from the file
               byte[] buffer = new byte[2048];
               int iBytesReads;

               // In each successful read, write back to the source
               while ((iBytesReads = fInStream.read(buffer)) >= 0) {
                    fOutStream.write(buffer, 0, iBytesReads);
               }

               // Safe exit
               if (fInStream != null) {
                    fInStream.close();
               }

               if (fOutStream != null) {
                    fOutStream.close();
               }
          }
     }
     catch (Exception ex) {
          // Please handle all the relevant exceptions here
     }
}