Getting the Directory Roots
Problem
You want to know about all the top-level directories, such as C:\ and D:\ on MS-Windows.
Solution
Use the static method File.listRoots( )
.
Discussion
Speaking of directory listings, you surely know that all modern
desktop computing systems arrange files into hierarchies of
directories. But you might not know that on
Unix all filenames are somehow
“under” the single root directory named
/
, while on Microsoft platforms there is a root
directory named \
in each disk drive (A:\ for the
first floppy, C:\ for the first hard drive, and other letters for
CD-ROM and network drivers). If you need to know about all the files
on all the disks, then, you should find out what “directory
root” names exist on the particular platform. The static method
listRoots( )
returns (in an array of
File
objects) the available filesystem roots on
whatever platform you are running on. Here is a short program to list
these, along with its output:
C:> type DirRoots.java import java.io.*; public class DirRoots { public static void main(String argh_my_aching_fingers[]) { File[] drives = File.listRoots( ); // Get list of names for (int i=0; i<drives.length; i++) System.out.println(drives[i]); // Print the list } } C:> java DirRoots A:\ C:\ D:\ C:>
As you can see, the program listed my floppy drive (even though the floppy drive was not only empty, but left at home while I wrote this recipe on my notebook computer in a parking lot), the hard disk drive, and the CD-ROM drive.
On Unix ...
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