Java Utility to Decompress a Zip File In Java

In the previous example we have seen “How to compress files/folder in java“. Now we will focus on “Java Utility to Decompress a Zip File In Java”

Java provides “java.util.zip” library to compress files/folder in zip format.

Steps to follow –

1. Take folder/files path as input.
2. Read the zip file using ZipInputStream
3. Get the zip file list entry ZipEntry, and output it using “FileOutputStream”.

package com.jkoder;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;

public class UnzipFolderExample {

	private final static String OUTPUt_FOLDER_NAME = "/opt/dev/report/";
	private final static String ZIP_FILE_NAME = "/opt/dev/report.zip";

	public static void main(String[] args) {
		byte[] buffer = new byte[1024];
		try {
			// check if output folder exist, if not create it
			File outputFolder = new File(OUTPUt_FOLDER_NAME);
			if (!outputFolder.exists()) {
				outputFolder.mkdir();
			}

			ZipInputStream zipfile = new ZipInputStream(new FileInputStream(
					ZIP_FILE_NAME));
			ZipEntry zipentry = zipfile.getNextEntry();

			while (zipentry != null) {
				String fileName = zipentry.getName();
				File newFile = new File(outputFolder + File.separator + fileName);

				FileOutputStream fos = new FileOutputStream(newFile);

				int len;
				while ((len = zipfile.read(buffer)) > 0) {
					fos.write(buffer, 0, len);
				}

				fos.close();
				zipentry = zipfile.getNextEntry();
			}

			zipfile.closeEntry();
			zipfile.close();
		} catch (IOException ex) {
			ex.printStackTrace();
		}
	}
}