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disk volume label

Posted on 2002-04-04
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Last Modified: 2008-02-01
how can i read the volume label of a disk?
i want to build a cd catalog-application
it just has to run on windows
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Question by:atombender
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6 Comments
 
LVL 9

Expert Comment

by:Ovi
ID: 6917882
If you want to use JDK 1.4 you don't have to ask yourself this question, itdoes automatically this for you. Try to use for example a JFileChooser from JDK1.4.

If not, I believe with native code invoked by Java (Using Runtime.getDefaultRuntime().execute("cmd") and reading from the input stream of the resulted process).
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Expert Comment

by:Ovi
ID: 6917885
Correction : (Using Runtime.getRuntime().execute("cmd") ....
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Author Comment

by:atombender
ID: 6917951
unfortunately i have jdk1.3
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Expert Comment

by:rashidkamranbs
ID: 6919037
import java.io.*;

public class Test{
     public static void main(String args[])throws Exception{
          Runtime rt=Runtime.getRuntime();
          Process p=rt.exec("chkdsk f:");
          BufferedReader in=new BufferedReader(new InputStreamReader(p.getInputStream()));
          System.out.println(in.readLine());
          System.out.println(in.readLine());
          p.destroy();
         
     }
}
OUT PUT IS
The type of the file system is FAT32.
Volume PROGRAMS created 10/22/2001 9:39 AM

Its a bit funny .. but belive me reads the Volume label and type of drive F, there on Windows XP with JRE 1.3.. if ya have ne other progam that could write the Disk Volume you can use instead.. as i used chkdsk.. no internal command i think

points as it works :-) kiddin
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LVL 3

Accepted Solution

by:
msterjev earned 100 total points
ID: 6919274
OK. Some JNI looks like this:

Kernel32.java


import java.util.*;

public class Kernel32
{
     static
     {
          System.loadLibrary("JKernel32");
     }
     
     private static native String getLogicalDriveStrings();
     public static native String getVolumeLabel(String root);
     
     public static Enumeration enumLogicalDrives()
     {
          Vector v=new Vector();
          String drives=getLogicalDriveStrings();
          StringTokenizer st=new StringTokenizer(drives);
          while(st.hasMoreTokens())
               v.addElement(st.nextToken());
          return v.elements();
     }
}


Generate header with javah:

javah Kernel32

Start Visual C++ and make new dll with the name JKernel32.
Import here previously generate Kernel32.h.

Insert new C++ file and type here:

#include "Kernel32.h"
#include <windows.h>

JNIEXPORT jstring JNICALL Java_Kernel32_getLogicalDriveStrings(JNIEnv * env, jclass c)
{
     char buffer[256]={0};
     char drives[256]={0};
     ::GetLogicalDriveStrings(256,buffer);
     char *p=buffer;
     lstrcpy(drives,"");
     while(*p!=0)
     {
          strncat(drives,p,3);
          strcat(drives," ");
          p+=4;
     }
     return
          env->NewStringUTF(drives);
}


JNIEXPORT jstring JNICALL Java_Kernel32_getVolumeLabel(JNIEnv * env, jclass c, jstring r)
{
     const char *root=env->GetStringUTFChars(r,0);
     char volumeNameBuffer[MAX_PATH];
    DWORD lVolumeSerialNumber=0;
     DWORD lMaximumComponentLength=0;
     DWORD lFileSystemFlags=0;
     char fileSystemNameBuffer[10];
     if(::GetVolumeInformation(root,volumeNameBuffer,MAX_PATH,&lVolumeSerialNumber,&lMaximumComponentLength,&lFileSystemFlags,fileSystemNameBuffer,10))
     {
          env->ReleaseStringUTFChars(r,root);
          return env->NewStringUTF(volumeNameBuffer);
     }
     env->ReleaseStringUTFChars(r,root);
     return NULL;
}


Compile the project and put  JKernel32.dll into the same directory as Kernel32 class.

Try this:

Test.java

import java.util.*;

public class Test
{
     public static void main(String[] args)
     {
          String drive,label;
          Enumeration e=Kernel32.enumLogicalDrives();
          while(e.hasMoreElements())
          {
               drive=(String)e.nextElement();
               label=Kernel32.getVolumeLabel(drive);
               System.out.println(drive+":"+label);
          }
     }
}

Enjoy.

P.S. JNI is such a cool thing. You can extend Java with almost everything you want!!!!
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LVL 3

Expert Comment

by:msterjev
ID: 6920402
Some comment.....
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