In this post we'll see a Java program showing how to untar a tar file. It has both the steps to first decompress a .tar.gz file and later untar it.
- Refer Creating tar file and GZipping multiple files to see how to create a tar file.
Using Apache Commons Compress
Apache Commons Compress library is used in the code for untarring a file. You can download it from here \– https://commons.apache.org/proper/commons-compress/download_compress.cgi.
Make sure to add commons-compress-xxx.jar in your application’s class path. I have used commons-compress-1.13 version.
Java example to untar a file
This Java program has two methods deCompressGZipFile() method is used to decompress a .tar.gz file to get a .tar file.
Using unTarFile() method this .tar file is untarred.
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.zip.GZIPInputStream;
import org.apache.commons.compress.archivers.tar.TarArchiveEntry;
import org.apache.commons.compress.archivers.tar.TarArchiveInputStream;
import org.apache.commons.compress.utils.IOUtils;
public class UnTarDemo {
public static void main(String[] args) {
// Path to input file, which is a
// tar file compressed to create gzip file
String INPUT_FILE = "G:\\Test.tar.gz";
// This folder should exist, that's where
// .tar file will go
String TAR_FOLDER = "G:\\TarFile";
// After untar files will go to this folder
String DESTINATION_FOLDER = "G:\\Temp";
UnTarDemo unTarDemo = new UnTarDemo();
try {
File inputFile = new File(INPUT_FILE);
String outputFile = getFileName(inputFile, TAR_FOLDER);
System.out.println("outputFile " + outputFile);
File tarFile = new File(outputFile);
// Calling method to decompress file
tarFile = unTarDemo.deCompressGZipFile(inputFile, tarFile);
File destFile = new File(DESTINATION_FOLDER);
if(!destFile.exists()){
destFile.mkdir();
}
// Calling method to untar file
unTarDemo.unTarFile(tarFile, destFile);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
/**
*
* @param tarFile
* @param destFile
* @throws IOException
*/
private void unTarFile(File tarFile, File destFile) throws IOException{
FileInputStream fis = new FileInputStream(tarFile);
TarArchiveInputStream tis = new TarArchiveInputStream(fis);
TarArchiveEntry tarEntry = null;
// tarIn is a TarArchiveInputStream
while ((tarEntry = tis.getNextTarEntry()) != null) {
File outputFile = new File(destFile + File.separator + tarEntry.getName());
if(tarEntry.isDirectory()){
System.out.println("outputFile Directory ---- "
+ outputFile.getAbsolutePath());
if(!outputFile.exists()){
outputFile.mkdirs();
}
}else{
//File outputFile = new File(destFile + File.separator + tarEntry.getName());
System.out.println("outputFile File ---- " + outputFile.getAbsolutePath());
outputFile.getParentFile().mkdirs();
//outputFile.createNewFile();
FileOutputStream fos = new FileOutputStream(outputFile);
IOUtils.copy(tis, fos);
fos.close();
}
}
tis.close();
}
/**
* Method to decompress a gzip file
* @param gZippedFile
* @param newFile
* @throws IOException
*/
private File deCompressGZipFile(File gZippedFile, File tarFile) throws IOException{
FileInputStream fis = new FileInputStream(gZippedFile);
GZIPInputStream gZIPInputStream = new GZIPInputStream(fis);
FileOutputStream fos = new FileOutputStream(tarFile);
byte[] buffer = new byte[1024];
int len;
while((len = gZIPInputStream.read(buffer)) > 0){
fos.write(buffer, 0, len);
}
fos.close();
gZIPInputStream.close();
return tarFile;
}
/**
* This method is used to get the tar file name from the gz file
* by removing the .gz part from the input file
* @param inputFile
* @param outputFolder
* @return
*/
private static String getFileName(File inputFile, String outputFolder){
return outputFolder + File.separator +
inputFile.getName().substring(0, inputFile.getName().lastIndexOf('.'));
}
}
That's all for this topic How to Untar a File in Java. If you have any doubt or any suggestions to make please drop a comment. Thanks!
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