How to create a zip file in Java

by Hussein Terek · July 27, 2019

In this tutorial, we show how to create a zip file from multiple files in Java.

Using ByteArrayOutputStream and ZipOutputStream classes provided by the JDK, you can generate a zip file out of multiple files.

The following utility method accepts a list of File objects and generates a zip file as a byte array:

public byte[] zipFiles(List<File> files){

byte[] result = null;

try (ByteArrayOutputStream fos = new ByteArrayOutputStream(); ZipOutputStream zipOut = new ZipOutputStream(fos);) {

for (File fileToZip : files) {

try (FileInputStream fis = new FileInputStream(fileToZip);) {

ZipEntry zipEntry = new ZipEntry(fileToZip.getName());

zipOut.putNextEntry(zipEntry);

IOUtils.copy(fis, zipOut);

}

zipOut.close();

fos.close();

result = fos.toByteArray();

}

catch (Exception ex)

{

ex.printStackTrace();

}

return result;

}

That’s it.