How can I convert a string into a GZIP Base64 string?

Question

I've been trying to figure out using GZIPOutputStream's and the like but have had no success with understanding them. All I want to do is convert a string of characters - "A string of characters" into a GZIP Base64 format. How can I do this?

By GZIP Base64 format, I mean the string is first compressed using GZIP, then converted into Base64.

Answer 1

Use the Apache Commons Codec Base64OutputStream.

Here's a sample class:

import java.util.zip.GZIPOutputStream;
import org.apache.commons.codec.binary.Base64OutputStream;

public class Test {
    public static void main(String[] args) {
        String text = "a string of characters";
        try {
            Base64OutputStream b64os = new Base64OutputStream(System.out);
            GZIPOutputStream gzip = new GZIPOutputStream(b64os);
            gzip.write(text.getBytes("UTF-8"));
            gzip.close();
            b64os.close();
        } catch (Throwable t) {
            t.printStackTrace();
        }
    }
}

Which outputs:

H4sIAAAAAAAAAEtUKC4pysxLV8hPU0jOSCxKTC5JLSoGAOP+cfkWAAAA

Under Linux, you can confirm this works with:

echo 'H4sIAAAAAAAAAEtUKC4pysxLV8hPU0jOSCxKTC5JLSoGAOP+cfkWAAAA' | base64 -d | gunzip

(Please note that on OSX, you should use base64 -D instead of base64 -d in the above command)

Which outputs:

a string of characters