[Libguestfs] How to run the java demo code contained in libguestfs package ???

[Richard W.M. Jones]

On Mon, May 23, 2011 at 03:05:28PM +0800, 毛宏 wrote:
> I would like to use libguestfs to manage the virtual disk images of
> virtual machines on XenServer, which is a virtualization platform.

What version of libguestfs and where did you get it from?

> When I try to do some test of the Java codes contained in the libguestfs package, the following error promped up:
> 
> Exception in thread "main" java.lang.UnsatisfiedLinkError: no guestfs_jni in java.library.path
> at java.lang.ClassLoader.loadLibrary(Unknown Source)
> at java.lang.Runtime.loadLibrary0(Unknown Source)
> at java.lang.System.loadLibrary(Unknown Source)
> at com.redhat.et.libguestfs.GuestFS.<clinit>(GuestFS.java:44)
> at test.GuestFS005Load.main(GuestFS005Load.java:27)
> 
> It seems that I need to build guestfs_jni before I could use libguestfs through Java. But I am not clear how to get this "guestfs_jni".......
> Does anybody know how to fix this problem? Thank you very very much!

If the *.so file is in some non-standard place, then you may need to
define java.library.path to be the directory containing
libguestfs_jni.so.1.  For example:

  java -Djava.library.path=/path/to/library Test

You may also need to set your classpath to contain the jar file.

On a Fedora host using the libguestfs-java Fedora package, I can run
libguestfs like this [see attachment for test program]:

  $ CLASSPATH=/usr/share/java/libguestfs-1.11.8.jar javac Test.java
  $ CLASSPATH=/usr/share/java/libguestfs-1.11.8.jar:. java Test
  $ virt-filesystems -a test.img --all --long
  Name         Type        VFS      Label  Size       Parent
  /dev/VG/LV1  filesystem  ext2     -      209715200  -
  /dev/VG/LV2  filesystem  unknown  -      209715200  -
  /dev/VG/LV1  lv          -        -      209715200  /dev/VG
  /dev/VG/LV2  lv          -        -      209715200  /dev/VG
  /dev/VG      vg          -        -      520093696  -
  /dev/sda     pv          -        -      520093696  -
  /dev/sda     device      -        -      524288000  -

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
New in Fedora 11: Fedora Windows cross-compiler. Compile Windows
programs, test, and build Windows installers. Over 70 libraries supprt'd
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import java.io.*;
import java.util.Map;
import com.redhat.et.libguestfs.*;

public class Test
{
    public static void main (String[] argv)
    {
        try {
            // Delete any previous test file if one was left around.
            File old = new File ("test.img");
            old.delete ();

            RandomAccessFile f = new RandomAccessFile ("test.img", "rw");
            f.setLength (500 * 1024 * 1024);
            f.close ();

            GuestFS g = new GuestFS ();
            g.add_drive ("test.img");
            g.launch ();

            g.pvcreate ("/dev/sda");
            g.vgcreate ("VG", new String[] {"/dev/sda"});
            g.lvcreate ("LV1", "VG", 200);
            g.lvcreate ("LV2", "VG", 200);

            g.mkfs ("ext2", "/dev/VG/LV1");

            g.close ();
        }
        catch (Exception exn) {
            System.err.println (exn);
            System.exit (1);
        }
    }
}