Make tar file by Java
I have produced following code to solve this problem. This code checks if any of files to be incorporated already exist in tar file and updates that entry. Later if it doesn't exist append to the end of archive.
import org.apache.commons.compress.archivers.ArchiveEntry;
import org.apache.commons.compress.archivers.tar.TarArchiveEntry;
import org.apache.commons.compress.archivers.tar.TarArchiveInputStream;
import org.apache.commons.compress.archivers.tar.TarArchiveOutputStream;
public class TarUpdater {
private static final int buffersize = 8048;
public static void updateFile(File tarFile, File[] flist) throws IOException {
// get a temp file
File tempFile = File.createTempFile(tarFile.getName(), null);
// delete it, otherwise you cannot rename your existing tar to it.
if (tempFile.exists()) {
tempFile.delete();
}
if (!tarFile.exists()) {
tarFile.createNewFile();
}
boolean renameOk = tarFile.renameTo(tempFile);
if (!renameOk) {
throw new RuntimeException(
"could not rename the file " + tarFile.getAbsolutePath() + " to " + tempFile.getAbsolutePath());
}
byte[] buf = new byte[buffersize];
TarArchiveInputStream tin = new TarArchiveInputStream(new FileInputStream(tempFile));
OutputStream outputStream = new BufferedOutputStream(Files.newOutputStream(tarFile.toPath()));
TarArchiveOutputStream tos = new TarArchiveOutputStream(outputStream);
tos.setLongFileMode(TarArchiveOutputStream.LONGFILE_POSIX);
//read from previous version of tar file
ArchiveEntry entry = tin.getNextEntry();
while (entry != null) {//previous file have entries
String name = entry.getName();
boolean notInFiles = true;
for (File f : flist) {
if (f.getName().equals(name)) {
notInFiles = false;
break;
}
}
if (notInFiles) {
// Add TAR entry to output stream.
if (!entry.isDirectory()) {
tos.putArchiveEntry(new TarArchiveEntry(name));
// Transfer bytes from the TAR file to the output file
int len;
while ((len = tin.read(buf)) > 0) {
tos.write(buf, 0, len);
}
}
}
entry = tin.getNextEntry();
}
// Close the streams
tin.close();//finished reading existing entries
// Compress new files
for (int i = 0; i < flist.length; i++) {
if (flist[i].isDirectory()) {
continue;
}
InputStream fis = new FileInputStream(flist[i]);
TarArchiveEntry te = new TarArchiveEntry(flist[i],flist[i].getName());
//te.setSize(flist[i].length());
tos.setLongFileMode(TarArchiveOutputStream.LONGFILE_GNU);
tos.setBigNumberMode(2);
tos.putArchiveEntry(te); // Add TAR entry to output stream.
// Transfer bytes from the file to the TAR file
int count = 0;
while ((count = fis.read(buf, 0, buffersize)) != -1) {
tos.write(buf, 0, count);
}
tos.closeArchiveEntry();
fis.close();
}
// Complete the TAR file
tos.close();
tempFile.delete();
}
}
If you use Gradle use following dependency:
compile group: 'org.apache.commons', name: 'commons-compress', version: '1.+'
I also tried org.xeustechnologies:jtar:1.1 but performance is way below the one provided by org.apache.commons:commons-compress:1.12
Notes about performance using different implementations:
Zipping 10 times using Java 1.8 zip:
- java.util.zip.ZipEntry;
- java.util.zip.ZipInputStream;
- java.util.zip.ZipOutputStream;
[2016-07-19 19:13:11] Before
[2016-07-19 19:13:18] After
7 seconds
Tar-ing 10 times using jtar:
- org.xeustechnologies.jtar.TarEntry;
- org.xeustechnologies.jtar.TarInputStream;
- org.xeustechnologies.jtar.TarOutputStream;
[2016-07-19 19:21:23] Before
[2016-07-19 19:25:18] After
3m55sec
shell call to Cygwin /usr/bin/tar - 10 times
[2016-07-19 19:33:04] Before
[2016-07-19 19:33:14] After
14 seconds
Tar-ing 100(hundred) times using org.apache.commons.compress:
- org.apache.commons.compress.archivers.ArchiveEntry;
- org.apache.commons.compress.archivers.tar.TarArchiveEntry;
- org.apache.commons.compress.archivers.tar.TarArchiveInputStream;
- org.apache.commons.compress.archivers.tar.TarArchiveOutputStream;
[2016-07-19 23:04:45] Before
[2016-07-19 23:04:48] After
3 seconds
Tar-ing 1000(thousand) times using org.apache.commons.compress:
[2016-07-19 23:10:28] Before
[2016-07-19 23:10:48] After
20 seconds
.tar archive files are not compressed. You have to run a file compression on it like gzip and turn it into something like .tar.gz.
If you just want to just archive a directory, take a look at:
- http://www.trustice.com/java/tar/
- http://code.google.com/p/jtar/
I would look at Apache Commons Compress.
There is an example part way down this examples page, which shows off a tar example.
TarArchiveEntry entry = new TarArchiveEntry(name);
entry.setSize(size);
tarOutput.putArchiveEntry(entry);
tarOutput.write(contentOfEntry);
tarOutput.closeArchiveEntry();
You can use the jtar - Java Tar library.
Taken from their site:
JTar is a simple Java Tar library, that provides an easy way to create and read tar files using IO streams. The API is very simple to use and similar to the java.util.zip package.
An example, also from their site:
// Output file stream
FileOutputStream dest = new FileOutputStream( "c:/test/test.tar" );
// Create a TarOutputStream
TarOutputStream out = new TarOutputStream( new BufferedOutputStream( dest ) );
// Files to tar
File[] filesToTar=new File[2];
filesToTar[0]=new File("c:/test/myfile1.txt");
filesToTar[1]=new File("c:/test/myfile2.txt");
for(File f:filesToTar){
out.putNextEntry(new TarEntry(f, f.getName()));
BufferedInputStream origin = new BufferedInputStream(new FileInputStream( f ));
int count;
byte data[] = new byte[2048];
while((count = origin.read(data)) != -1) {
out.write(data, 0, count);
}
out.flush();
origin.close();
}
out.close();