This tutorial is intended to show how Java programming language can be used to unzip a zip file. This program currently unzips a .zip extension.
Here are some features that I would like to highlight:
- You can hard code the zip file location and destination extraction location and then run the program.
- Alternately, you can pass these as an argument from the console.
- If you pass the parameters from the console, hard coded parameters will be discarded.
- This program does not maintain the folder structure.
- It unzips all the files into a given destination directory.
- You can tweak this program to unzip the file to the proper directory structures.
- This file unzipping tutorial uses standard Java API.
- You are free to modify and distribute this source code. Please honor my work by attributing back to my blog.
package com.kushal.utilities;
import java.io.*;
import java.util.*;
import java.util.zip.*;
public class MyUnzipUtil {
public static final void main(String[] args) {
/**
* Initialize the default parameters
*/
String zipFileName = "C:/myFolder/myZip.zip";
String directoryToExtractTo = "C:/myFolder/unzipped/";
/**
* Check if the arguments are passed from console.
* If so, we will discard the defalt parameters.
*/
if (args.length != 2) {
System.err.println("Usage: MyUnzipUtil zipfile unzipLocation");
System.err.println("...Using The Hardcoded Zip Location");
} else {
zipFileName = args[0];
directoryToExtractTo = args[1];
}
/**
* Call the unzip method
*/
unzipMyZip(zipFileName, directoryToExtractTo);
}
/**
* This method
* --Reads an input stream
* --Writes the value to the output stream
* --Uses 1KB buffer.
*/
public static final void writeFile(InputStream in, OutputStream out)
throws IOException {
byte[] buffer = new byte[1024];
int len;
while ((len = in.read(buffer)) >= 0)
out.write(buffer, 0, len);
in.close();
out.close();
}
public static void unzipMyZip(String zipFileName,
String directoryToExtractTo) {
Enumeration entriesEnum;
ZipFile zipFile;
try {
zipFile = new ZipFile(zipFileName);
entriesEnum = zipFile.entries();
File directory= new File(directoryToExtractTo);
/**
* Check if the directory to extract to exists
*/
if(!directory.exists())
{
/**
* If not, create a new one.
*/
new File(directoryToExtractTo).mkdir();
System.err.println("...Directory Created -"+directoryToExtractTo);
}
while (entriesEnum.hasMoreElements()) {
try {
ZipEntry entry = (ZipEntry) entriesEnum.nextElement();
if (entry.isDirectory()) {
/**
* Currently not unzipping the directory structure.
* All the files will be unzipped in a Directory
*
**/
} else {
System.err.println("Extracting file: "
+ entry.getName());
/**
* The following logic will just extract the file name
* and discard the directory
*/
int index = 0;
String name = entry.getName();
index = entry.getName().lastIndexOf("/");
if (index > 0 && index != name.length())
name = entry.getName().substring(index + 1);
System.out.println(name);
writeFile(zipFile.getInputStream(entry),
new BufferedOutputStream(new FileOutputStream(
directoryToExtractTo + name)));
}
} catch (Exception e) {
e.printStackTrace();
}
}
zipFile.close();
} catch (IOException ioe) {
System.err.println("Some Exception Occurred:");
ioe.printStackTrace();
return;
}
}
}
