can i use java to check the disk usage?

[rosy Jovita]

Hi all,

is it possible to collect information about the disk usage.
for example: total space for local c:\, total used and total free.
can i do this in pure java?Thanks for any replies.

[Carey Brown]

Here's 3 source files that I pulled out of one of my projects which should get you started (hope I got them all, if not, let me know).

import java.io.File;


public class DirSize
{
	private static final String		SPACES =
		". . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ";

	public static void main( String[] args )
	{
		try
		{
			File	f = new File( args[0] );
			Dir		d = new Dir( null, f );
			process( d );
			long	limit = 30 * 1024 * 1024;
			print( d, limit, d.sum, 0 );
		}
		catch( Exception ex )
		{
			ex.printStackTrace();
		}
	}

	private static String spaces( int n )
	{
		return SPACES.substring( 0, n*2 );
	}

	private static void print( Dir dir, long limit, long rootSum, int indent )
	{
		if( dir.sum < limit )
			return;
		System.out.format( "%,16d %5.1f %s%s\r\n",
			dir.sum,
			(dir.parent==null)?100.0:(dir.sum*100.0/rootSum),
			spaces(indent),
			dir.file.getName()
			);
		for( Dir d : dir.children )
			print( d, limit, rootSum, indent+1 );
	}

	private static void process( Dir dir )
	{
		File[]		fileAry = dir.listFiles();
		if( fileAry != null )
		{
			for( File f : fileAry )
			{
				if( f.isFile() )
					dir.addLength( f.length() );
				else if( f.isDirectory() )
					process( new Dir( dir, f ) );
			}
		}

		dir.sortChildren();
	}
}
   

import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collections;

public class Dir
{
	private static DirOrderBySumDesc	dirOrderBySumDesc = new DirOrderBySumDesc();
	private static final long			KL = 1024L;
	private static final long			ML = 1024L * KL;
	private static final long			GL = 1024L * ML;
	private static final long			TL = 1024L * GL;
	private static final double			KD = KL;
	private static final double			MD = ML;
	private static final double			GD = GL;
	private static final double			TD = TL;

	Dir				parent;
	ArrayList<Dir>	children = new ArrayList<Dir>();
	File			file;
	long			sum;
	int				count;

	public Dir()
	{
	}

	public Dir( Dir parent, File file )
	{
		this.parent = parent;
		this.file = file;
		if( parent != null )
			parent.children.add( this );
	}

	public void addLength( long len )
	{
		sum += len;
		for( Dir p=parent ; p != null ; p = p.parent )
			p.sum += len;
	}

	public File[] listFiles()
	{
		return file.listFiles();
	}

	public void sortChildren()
	{
		Collections.sort( children, dirOrderBySumDesc );
	}

	public double percent()
	{
		if( parent == null )
			return 100.0;
		long		rootSum = 0;
		for( Dir p=parent ; p != null ; p = p.parent )
			rootSum = p.sum;
		return sum * 100.0 / rootSum;
	}

	private static String sizeString( long size )
	{
		if( size >= TL )
			return String.format( "%.1fT", size / TD );
		if( size >= GL )
			return String.format( "%.1fG", size / GD );
		if( size >= ML )
			return String.format( "%.1fM", size / MD );
		if( size >= KL )
			return String.format( "%.1fK", size / KD );
		return String.format( "%d", size );
	}

	@Override
    public String toString()
	{
		if( file == null )
			return String.format( "%s %5.1f%% (search results)",
				sizeString(sum), percent() );

		String	name = file.getName();
		if( name.length() == 0 )
		{
	        try
            {
	            name = file.getCanonicalPath();
            }
            catch( IOException e )
            {
	            e.printStackTrace();
            }
		}
        else if( name.equals( "(free)" ) )
           	name = file.getPath();
		return String.format( "%s %5.1f%% %s",
				sizeString(sum), percent(), name );
	}
}
    

import java.util.Comparator;


public class DirOrderBySumDesc
implements Comparator<Dir>
{
	public int compare( Dir arg0, Dir arg1 )
    {
		if( arg0.sum < arg1.sum )	return  1;
		if( arg0.sum > arg1.sum )	return -1;
		return 0;
    }
}
    

[Joe Ess]

Or you could use the methods of java.io.File like getFreeSpace() and getTotalSpace().

[Rob Spoor]

Joe Ess wrote:Or you could use the methods of java.io.File like getFreeSpace() and getTotalSpace().

+1. These got added in Java 6. Note that they are not static methods, because the values (may) differ for each root. Simply create a new file for C:\:

File root = new File("C:\\");
long total = root.getTotalSpace();
long free = root.getFreeSpace();
long usable = root.getUsableSpace();

You can also use File.listRoots() to list all roots, then call these methods on those.

[rosy Jovita]

Hi Carey,

thanks, it works.

and joe, thanks for the suggestion.

and Rob, that was very helpful:D

Thanks guys.

[Rob Spoor]

You're welcome.