How to convert ArchiveEntry to InputStream?

Question

I'm reading a tar.gz archive using

ArchiveEntry entry = tarArchiveInputStream.getNextEntry();

Question: how can I convert this ArchiveEntry to an InputStream so I can actually read and process the file to a String?

Answer 1

It is already an InputStream.

byte[] buf = new byte[(int) entry.getSize()];
int k = tarArchiveInputStream.read(buf, 0, buf.length);
String s = new String(buf, 0, k);

Answer 2

You could use IOUtils to read InputStream fully:

import org.apache.commons.compress.utils.IOUtils

byte[] buf = new byte[(int) entry.getSize()];
int readed  = IOUtils.readFully(tarArchiveInputStream,buf);

//readed should equal buffer size
if(readed != buf.length) {
 throw new RuntimeException("Read bytes count and entry size differ");
}

String string = new String(buf, StandardCharsets.UTF_8);

If your file is in other encoding than utf-8, use that instead of utf-8 in the constructor of string.

Answer 3

If you really want to read the file one by one, the TarEntry actually holds the File object in it:

This class represents an entry in a Tar archive. It consists of the entry's header, as well as the entry's File.

Thus just initialize another FileInputStream would be enough:

import org.apache.commons.io.IOUtils;
String file = IOUtils.toString(new FileInputStream(entry.getFile());