archive.tar
 +- tardir/
     +- content.txt.gz

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     +- non-gzip.txt

ls -l > content.txt
gzip content.txt
ls -l > non-gzip.txt
mkdir tardir
mv content.txt.gz non-gzip.txt tardir
tar cvf archive.tar tardir
rm -r tardir

FileSystemManager fsManager = VFS.getManager();
FileObject file = fsManager.resolveFile( "gz:tar:file:///extra/data/tryVfs/archive.tar!/tardir/content.txt.gz!content.txt" );

if (extractFile.getName().getExtension().equals("gz"))

if (manager.canCreateFileSystem(extractFile))
{
    FileObject innerFile = manager.createFileSystem(extractFile);
}

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>gov.noaa.eds</groupId>
    <artifactId>tryVfs</artifactId>
    <packaging>jar</packaging>
    <version>1.0-SNAPSHOT</version>
    <name>Try apache commons vfs</name>
    <url>http://maven.apache.org</url>
    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <source>1.5</source>
                    <target>1.5</target>
                </configuration>
            </plugin>
            <plugin>
                <!-- Usage: mvn assembly:assembly -->
                <artifactId>maven-assembly-plugin</artifactId>
                <configuration>
                    <descriptorRefs>
                        <descriptorRef>jar-with-dependencies</descriptorRef>
                    </descriptorRefs>
                    <archive>
                        <manifest>
                            <mainClass>gov.noaa.eds.tryVfs.MultiStep</mainClass>xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>gov.noaa.eds</groupId>
    <artifactId>tryVfs</artifactId>
    <packaging>jar</packaging>
        </manifest><version>1.0-SNAPSHOT</version>
    <name>Try apache commons vfs</name>
    <url>http://maven.apache.org</url>
         </archive><build>
        <plugins>
        </configuration>
    <plugin>
        </plugin>
        </plugins><groupId>org.apache.maven.plugins</groupId>
    </build>
    <dependencies>
        <dependency><artifactId>maven-compiler-plugin</artifactId>
            <groupId>commons-vfs</groupId>
    <configuration>
        <artifactId>commons-vfs</artifactId>
            <version>1<source>1.0<5</version>source>
        </dependency>
        <dependency>
       <target>1.5</target>
     <groupId>junit</groupId>
            <artifactId>junit<</artifactId>configuration>
            <version>3.8.1</version></plugin>
            <scope>test</scope><plugin>
        </dependency>
     </dependencies>
</project>

/*
 * ExtractFromGzipInTar.java
 */
package gov.noaa.eds.tryVfs;

import org.apache.commons.vfs.AllFileSelector;
import org.apache.commons.vfs.FileName;
import org.apache.commons.vfs.FileObject;
import org.apache.commons.vfs.FileSystemException;
import org.apache.commons.vfs.FileSystemManager;
import org.apache.commons.vfs.FileType;
import org.apache.commons.vfs.FileTypeSelector;
import org.apache.commons.vfs.VFS;
import org.apache.commons.vfs.provider.local.LocalFile;

/**
 * Try using VFS to read the content of a compressed (gz) file inside of
 * a tar file. Extract tar file objects. If they are gzip files, decompress them.
 * Any directory structure in the tarfile is not being preserved, the contents
 * are pulled out to the same location regardless of directory hierarchy (for
 * the purposes of this example, all objects in the tar file have unique names,
 * so there are no file name conflicts).
 *
 * @author Ken Tanaka
 */
public class ExtractFromGzipInTar 
{
    FileSystemManager fsManager = null;
    static String extractDirname = "/extra/data/tryVfs";
    
    /**
     * Extract files from a tar file. If the file extracted is gzipped,
     * decompress it and remove the gzipped version.
     * @param args command line arguments are currently not used
     */
    public static void main( String[] args )
    {                + extractDirname);
            if (! msExtract.extractDir.exists()) {
                msExtract.extractDir.createFolder();
            }
        } catch (FileSystemException ex) {
            throw new RuntimeException("failed to prepare extract directory " 
                    + extractDirname, ex);
        }
        
        
        /* Create a tarFile object */
        FileObject tarFile;
        try {
            System.out.println("Resolve tar file:");
            tarFile = msExtract.fsManager.resolveFile(
                    "tar:/extra/data/tryVfs/archive.tar");
            
            FileName tarFileName = tarFile.getName();
        ExtractFromGzipInTar extract = new System.out.println("  PathExtractFromGzipInTar();
      : " + tarFileName.getPath());
        try {
   System.out.println("  URI      : "extract.fsManager += tarFileNameVFS.getURIgetManager());
        } catch (ExceptionFileSystemException ex) {
            throw new RuntimeException("failed to openget tarfsManager filefrom VFS", ex);
        }
        
        /* Work on files inside tarFile */}
        FileObject[] children;
        try {
        /* Create a tarFile childrenFileObject = tarFile.getChildren();
        } catch (FileSystemException ex) {
to connect to the tarfile on disk */
        FileObject tarFile;
       throw new RuntimeException("failed to get contents of tarfile ", ex);
try {
            String tarName = }
     new String("tar:file://" + extractDirname + "/archive.tar");
   
        for (FileObject f : children) {
System.out.println("Resolve " + tarName);
            tarFile = msExtractextract.fsManager.processChildresolveFile(ftarName);
         }
   
      
    } // main( String[] args )FileName tarFileName = tarFile.getName();
    
      private void processChild(FileObject f) {
System.out.println("  Path     : "  try {+ tarFileName.getPath());
            if (f.getType() == FileType.FOLDER) {
 System.out.println("  URI      : " + tarFileName.getURI());
      // Recursively process} filescatch in(Exception thisex) folder{
            throw new RuntimeException("failed  FileObject[] children = f.getChildren(to open tar file ", ex);
        }
        for (FileObject subfile : children) {

        /* Work on files inside tarFile */
         processChild(subfile)FileObject[] children;
        try {
       }
     children = tarFile.getChildren();
        } elsecatch (FileSystemException ex) {
            throw new RuntimeException("failed to get contents FileNameof fnametarfile = f.getName(", ex);
        }
        String
 extractName = new String(this.extractDir.getName() + "/"
  for (FileObject f : children) {
            extract.processChild(f);
     + fname.getBaseName());
   }
    } // main( String[] args )
    
    System.out.println("Extracting " + extractName);private void processChild(FileObject f) {
        try {
        LocalFile   extractFile =if (LocalFile) this.fsManager.resolveFile(extractName);f.getType() == FileType.FOLDER) {
                extractFile.copyFrom(f, new AllFileSelector());
// Recursively process files in this folder
                FileObject[] children = f.getChildren();
                // if the file is gzipped, decompress it
for (FileObject subfile : children) {
                   if processChild(extractFile.getName().getExtension().equals("gz")) {subfile);
                }
    System.out.println("Decompressing " + extractName);
      } else {
             String gzName = new String("gz://" + extractFileFileName fname = f.getName().getPath());
                String extractName = new System.out.printlnString("gzName="file://" + extractDirname + gzName);"/"
                    FileObject   gzFile =+ thisfname.fsManager.resolveFilegetBaseName(gzName));
                    String fileName = extractFile.getName().getBaseName().replaceAll(".gz$", ""System.out.println("Extracting " + extractName);
                LocalFile extractFile = (LocalFile) this.fsManager.resolveFile(extractName);
                   
 // The decompressed path we want
          // if the file is gzipped, decompress it
/* line  String90 decompName*/ = newif String(thisextractFile.extractDirgetName().getNamegetExtension() + "/" .equals("gz")) {
                            + fileNameSystem.out.println("Decompressing " + extractName);
                    
                    // AThe temporary Directory
              uncompressed filename we seek
      String tmpDirname = new String(this.extractDir.getName() + "/" 
       // content.txt
                    +String fileName + ".tmp= extractFile.getName().getBaseName().replaceAll(".gz$", "");
                    
                    // A temporary file path
                    String tmpFilename = new String(tmpDirname + "/" + fileName);
 Build the direct path to the uncompressed content of the 
                    // gzip file in the tar file.
                    // Some debug lines
     gz:tar:file:///archive.tar!/tardir/content.txt.gz!content.txt
/* line 100 */      String gzName = new String("gz:" +    System.out.println("fileName   =fname.getURI() + "!" + fileName);
                    System.out.println("decompName =" + decompName);
                 FileObject gzFile = Systemthis.outfsManager.println("tmpDirname =" + tmpDirname);
resolveFile(gzName);
                    
   System.out.println("tmpFilename=" + tmpFilename);
               // The decompressed path we want
                    String decompName = new String("file://" Extracting+ extractDirname from+ gzip"/" file
 ends up with a directory containing what
                    // we want.+ fileName);
                    LocalFile tmpDirdecompFile = (LocalFile) this.fsManager.resolveFile(tmpDirnamedecompName);
                    tmpDir.copyFrom(gzFile, new FileTypeSelector(FileType.FILE));
                    
// Some debug lines
                 // Move the uncompressed file to the location desired. System.out.println("fileName   =" + fileName);
                    LocalFile tmpFile = (LocalFile) this.fsManager.resolveFile(tmpFilenameSystem.out.println("decompName =" + decompName);
                    LocalFile decompFile = (LocalFile) this.fsManager.resolveFile(decompNameSystem.out.println("gzName=" + gzName);
                    tmpFile.moveTo(decompFile);

                    // Extracting
       
             decompFile.copyFrom(gzFile, new FileTypeSelector(FileType.FILE));
     // Delete the temporary directory.
       } else {
           tmpDir.delete(new AllFileSelector());
        // just extract the non-gzip file
       
             extractFile.copyFrom(f, new AllFileSelector());
     // Delete the gzip file now that we have the uncompressed version.}
            }
        //} Notecatch that the plain file FileObject (extractFile) is used (FileSystemException ex) {
              ex.printStackTrace();
      // for deleting instead of the gzipthrow FileObjectnew (gzFile).
      RuntimeException("Error working on tarfile object " + f.getName());
        }
    } // extractFile.deleteprocessChild(newFileObject AllFileSelector());
                }
            }
        } catch (FileSystemException ex) {
            ex.printStackTrace();
            throw new RuntimeException("Error working on tarfile object " + f.getName());
        }
    } // processChild(FileObject f)
}

f)
}

mvn assembly:assembly

java -jar target/tryVfs-1.0-SNAPSHOT-jar-with-dependencies.jar

Nov 7, 2007 12:22:01 PM org.apache.commons.vfs.VfsLog info
INFO: Using "/tmp/vfs_cache" as temporary files store.
Resolve tar:file:///extra/data/tryVfs/archive.tar
  Path     : /
  URI      : tar:file:///extra/data/tryVfs/archive.tar!/
Extracting file:///extra/data/tryVfs/non-gzip.txt
Extracting file:///extra/data/tryVfs/content.txt.gz
Decompressing file:///extra/data/tryVfs/content.txt.gz
fileName   =content.txt
decompName =file:///extra/data/tryVfs/content.txt
gzName=gz:tar:file:///extra/data/tryVfs/archive.tar!/tardir/content.txt.gz!content.txt