Uncompress a GZIP string in Java

Question

Possible Duplicate:
How to decompress a gzipped data in a byte array?

I have a Gzip'd byte array and I simply want to uncompress it and print the output. It's something like this:

byte[] gzip = getGZIPByteArray();

/* Code do uncompress the GZIP */

System.out.print(uncompressedGZIP);

Can anybody help me with the code in the middle?

score 19 · Accepted Answer · edited May 25 '17 at 03:20

// With 'gzip' being the compressed buffer
java.io.ByteArrayInputStream bytein = new java.io.ByteArrayInputStream(gzip);
java.util.zip.GZIPInputStream gzin = new java.util.zip.GZIPInputStream(bytein);
java.io.ByteArrayOutputStream byteout = new java.io.ByteArrayOutputStream();

int res = 0;
byte buf[] = new byte[1024];
while (res >= 0) {
    res = gzin.read(buf, 0, buf.length);
    if (res > 0) {
        byteout.write(buf, 0, res);
    }
}
byte uncompressed[] = byteout.toByteArray();

score 14 · Answer 2 · answered Sep 21 '12 at 13:38

14

The below method may give you a start :-

    public static byte[] decompress(byte[] contentBytes){
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        try{
            IOUtils.copy(new GZIPInputStream(new ByteArrayInputStream(contentBytes)), out);
        } catch(IOException e){
            throw new RuntimeException(e);
        }
        return out.toByteArray();
    }

Ensure that you have the below in your classpath and import them in your code.

import java.util.zip.*;
import org.apache.commons.io.IOUtils;

answered Sep 21 '12 at 13:38

verisimilitude

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This depends on apache commons IO api, which is not part of a standard Java distribution. – NovaDenizen Sep 21 '12 at 14:01
maybe you can add the compress function as well ? – RonTLV Oct 15 '18 at 12:40

Uncompress a GZIP string in Java

2 Answers2