How to Decompress Byte Array in Java

In this example, let’s  see  how to decompress byte array in Java.

Source Code

package com.beginner.examples;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.util.zip.GZIPInputStream;
import java.util.zip.GZIPOutputStream;

public class DecompressByte {

	public static void main(String[] args) {
		byte[] bytes = doCompressArray("Hello World".getBytes());
		bytes = doDecompressByte(bytes);
		System.out.println(new String(bytes));
	}
	
	/**
	 * 
	 * @breif: java.util.zip package provides Inflater class to decompress byte array.
	 * @param: data
	 * @return
	 */
	public static byte[] doDecompressByte(byte[] data) {
		byte[] b = null;
		try {
			ByteArrayInputStream bis = new ByteArrayInputStream(data);
			GZIPInputStream gzip = new GZIPInputStream(bis);
			byte[] buf = new byte[1024];
			int num = -1;
			ByteArrayOutputStream baos = new ByteArrayOutputStream();
			while ((num = gzip.read(buf, 0, buf.length)) != -1) {
				baos.write(buf, 0, num);
			}
			b = baos.toByteArray();
			baos.flush();
			baos.close();
			gzip.close();
			bis.close();
		} catch (Exception e) {
			e.printStackTrace();
		}
		return b;
	}
	
	public static byte[] doCompressArray(byte[] data) {
		byte[] b = null;
		try {
			ByteArrayOutputStream bos = new ByteArrayOutputStream();
			GZIPOutputStream gzip = new GZIPOutputStream(bos);
			gzip.write(data);
			gzip.finish();
			gzip.close();
			b = bos.toByteArray();
			bos.close();
		} catch (Exception e) {
			e.printStackTrace();
		}
		return b;
	}
}

Output:

Hello World

References

Imported packages in Java documentation:

• ByteArrayInputStream
• ByteArrayOutputStream
• GZIPInputStream
• GZIPOutputStream