How to read drive letter. i.e (c:, d:, e:) when drive is labelled

[gauravkv gupta]

while simulating <dir> command of DOS, i need to get drive letter of the drive.
For the output:
D:\>cd android-sdks

D:\android-sdks>dir
Volume in drive D is my labeled drive

how i will get the drive letter(D) in my code.

[Carey Brown]

Try javax.swing.filechooser.FileSystemView. Although it is in the Swing package this class does not require that it be a part of a Swing application.

[Carey Brown]

After reading you post again I'm not sure I was answering the right question. What exactly is your input and what are you expecting as output? If you are starting out with a File, you can get the drive letter by looking at the first character of File.getAbsolutePath() [only true for windows of course].

[gauravkv gupta]

Carey Brown wrote:After reading you post again I'm not sure I was answering the right question. What exactly is your input and what are you expecting as output? If you are starting out with a File, you can get the drive letter by looking at the first character of File.getAbsolutePath() [only true for windows of course].

Yeah you are right. Thanks for the answer. but now i want to get the label of D drive also which is "My Labeled Drive".
How to get the label.

[Carey Brown]

gauravkv gupta wrote:

Carey Brown wrote:After reading you post again I'm not sure I was answering the right question. What exactly is your input and what are you expecting as output? If you are starting out with a File, you can get the drive letter by looking at the first character of File.getAbsolutePath() [only true for windows of course].

Yeah you are right. Thanks for the answer. but now i want to get the label of D drive also which is "My Labeled Drive".
How to get the label.

For the drive label see FileSystemView.

[Mohamed Sanaulla]

Java 7 has few APIs to get this information.
Each file location/directory location can be represented using instance of Path class and to obtain an instance of Path you need to make use of the Paths.get(location) API.

Each Path instance has a number of components to it: File Name, Parent and Root. In your case you would be looking for a Root element which can be obtained using pathInstance.getRoot()

[Carey Brown]

Mohamed Sanaulla wrote:Java 7 has few APIs to get this information.
Each file location/directory location can be represented using instance of Path class and to obtain an instance of Path you need to make use of the Paths.get(location) API.

Each Path instance has a number of components to it: File Name, Parent and Root. In your case you would be looking for a Root element which can be obtained using pathInstance.getRoot()

Couldn't quite see how you would get from a Path to a drive label.

This is an Fsv class that wraps around the FileSystemView class. Its main method just prints out all of the root file systems. The output I get looks something like this: (Only better. The post really screwed up the columns.)

C=Computer, D=Drive, S=File_System, R=Root, T=Type, L=Drive_Letter
CDSRT  Type                            Name                                           Total        Available  Free   L Path            
-----  ------------------------------ ----------------------------------------  ----------  ---------   - ----   - ----------------
-TTT1  Local Disk                      DRIVE_C                                          1.8 TB 1,010.2 GB    54% C C:\
-TTT1  Local Disk                      DRIVE_D                                      931.5 GB    790.2 GB   85% D D:\
-TTT6  Removable Disk             EOS_DIGITAL                                 29.8 GB      29.8 GB 100% E E:\
-TTT6  Removable Disk                                                                                                          F F:\
-TTT2  CD Drive                                                                                                                    H H:\
-TTT2  CD Drive                                                                                                                    I I:\
-TTT1  Local Disk                      MYBOOK6                                         1.8 TB       1.1 TB   60% M M:\

import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import javax.swing.filechooser.FileSystemView;


public class Fsv
{
	private static final FileSystemView	fileSystemView = FileSystemView.getFileSystemView();
	private static final Pattern		pat = Pattern.compile( "(.*?)( \\([A-Za-z]:\\))(.*)" );
	private static ArrayList<Fsv>		rootCache = new ArrayList<Fsv>();		// TODO
	public static final String[]		FSV_TYPES =
	{
		"Unknown",
		"Local Disk",
		"CD Drive",
		"Network Drive",
		"Disconnected Network Drive",
		"File Folder",
		"Removable Disk"
	};
	public static final int			FSV_TYPE_UNKNOWN 		= 0;
	public static final int			FSV_TYPE_LOCAL_DISK		= 1;
	public static final int			FSV_TYPE_CD_DRIVE		= 2;
	public static final int			FSV_TYPE_NETWORK_DRIVE	= 3;
	public static final int			FSV_TYPE_DISCONNECTED_NETWORK_DRIVE = 4;
	public static final int			FSV_TYPE_FILE_FOLDER	= 5;
	public static final int			FSV_TYPE_REMOVABLE_DISK = 6;
	public static final long		K = 1024L;
	public static final long		M = 1024L * 1024L;
	public static final long		G = 1024L * 1024L * 1024L;
	public static final long		T = 1024L * 1024L * 1024L * 1024L;

	private String			drive = "";
	private String			path = "";
	private boolean			isComputer;			// always false
	private boolean			isDrive;
	private boolean			isFileSystem;
	private boolean			isFileSystemRoot;
	private String			type = "";
	private String			name = "";
	private int				typeId;
	private long			totalSpace;
	private long			usableSpace;

	public Fsv( File f )
	{
		try
		{
			path = f.getCanonicalPath();
		}
		catch( IOException e )
		{
			path = f.getPath();
			System.err.println( "ERR Can't compute canonical path for: '" + path + "'" );
		}
		if( path.length() > 1 && path.charAt( 1 ) == ':' )
			drive = path.substring( 0, 1 );

		type	= fileSystemView.getSystemTypeDescription( f );
		typeId	= getTypeIndex( type );
		name	= fileSystemView.getSystemDisplayName( f );
		Matcher		m;
		if( (m = pat.matcher( name )).matches() )
		{
			name = m.group(1);
			if( m.group(3).length() > 0 )
				name = name + " -" + m.group(3);
		}

		isComputer			= fileSystemView.isComputerNode( f );		// always false
		isDrive				= fileSystemView.isDrive( f );
		isFileSystem		= fileSystemView.isFileSystem( f );
		isFileSystemRoot	= fileSystemView.isFileSystemRoot( f );

		if( isFileSystemRoot )
		{
			totalSpace = f.getTotalSpace();
			usableSpace = f.getUsableSpace();
		}
	}

	// TODO need to cache roots
	public static Fsv[] listRoots()
	{
		File[]		ary = File.listRoots();
		Fsv[]		components = new Fsv[ ary.length ];
		Fsv			comp;
		for( int i=0 ; i < ary.length ; i++ )
		{
			comp = components[i] = new Fsv( ary[i] );
			if( comp.getTypeId() == FSV_TYPE_DISCONNECTED_NETWORK_DRIVE )
			{
				try
				{
					Thread.sleep( 500 ); // seems to work but may takes too long
					comp = components[i] = new Fsv( ary[i] );
				}
				catch( InterruptedException ex )
				{
				}
			}
		}
		return components;
	}

	public static Fsv findDrive( String drive )
	{
		for( Fsv fsv : listRoots() )
			if( fsv.getDrive().equals( drive ) )
				return fsv;
		return null;
	}

	public static void printRoots()
	{
		printHeader();
		for( Fsv fsv : listRoots() )
			System.out.println( fsv );
	}
	
	public static void print( File f )
	{
		File[]		ary = new File[ 1 ];
		ary[ 0 ] = f;
		print( ary );
	}

	public static void print( File[] ary )
	{
		for( File f : ary )
			System.out.println( new Fsv( f ) );
	}

	public static int getTypeIndex( String type )
	{
		for( int i=1 ; i < FSV_TYPES.length ; i++ )
			if( FSV_TYPES[ i ].equalsIgnoreCase( type ) )
				return i;
		return 0;
	}

	public static String getTypeName( int index )
	{
		return FSV_TYPES[ index ];
	}

	public String spaceUsage()
	{
		if( ! isFileSystemRoot || totalSpace == 0 )
			return "";
		return String.format( "%10s %10s %3.0f%%",
				length( totalSpace ),
				length( usableSpace ),
				usableSpace * 100.0 / totalSpace
				);
	}

	public static String length( long len )
	{
		String			s;
		if     ( len < K )	s = String.format( "%,d.0  B", len );
		else if( len < M )	s = String.format( "%,.1f KB", (double)len / K );
		else if( len < G )	s = String.format( "%,.1f MB", (double)len / M );
		else if( len < T )	s = String.format( "%,.1f GB", (double)len / G );
		else			    s = String.format( "%,.1f TB", (double)len / T );
		return s;
	}

	public static void printHeader()
	{
		System.out.println( "C=Computer, D=Drive, S=File_System, R=Root, T=Type, L=Drive_Letter" );
		System.out.println( "CDSRT  Type                           Name                                     Total      Available  Free L Path            " );
		System.out.println( "-----  ------------------------------ ---------------------------------------- ---------- ---------- ---- - ----------------" );
	}

	@Override
    public String toString()
	{
		return String.format( "%s%s%s%s%d  %-30s %-40s %26s %1s %s",
			isComputer		? "T" : "-",
			isDrive			? "T" : "-",
			isFileSystem	? "T" : "-",
			isFileSystemRoot ? "T" : "-",
			typeId,
			type,
			name,
			spaceUsage(),
			drive,
			path
			);
	}

	public String		getDrive()			{ return drive; }
	public String		getPath()			{ return path; }
	public boolean		isComputer()		{ return isComputer; }
	public boolean		isDrive()			{ return isDrive; }
	public boolean		isFileSystem()		{ return isFileSystem; }
	public boolean		isFileSystemRoot()	{ return isFileSystemRoot; }
	public String		getType()			{ return type; }
	public String		getName()			{ return name; }
	public int			getTypeId()			{ return typeId; }
	public long			getTotalSpace()		{ return totalSpace; }
	public long			getUsableSpace()	{ return usableSpace; }

	public static void main( String[] args )
	{
		printRoots();
	}
}

[Mohamed Sanaulla]

Carey Brown wrote: Couldn't quite see how you would get from a Path to a drive label.

There are a few new APIs added as part of the Java 7 NIO2 enhancements and java.nio.file.Path, java.nio.file.Paths, FileSystem and FileSystems are one among them. They allow you to access the details of the underlying file system. java.file.nio.Paths is used to get an instance of java.nio.file.Path and FileSystems is used to get an instance of FileSystem. If the OP is using Java 7 I suggested to look at these APIs.