How do I decompress Java objects?

In the previous example How do I compress Java objects? we have manage to compress Java objects and stored them in file. In this example we will read the file and reconstruct the compressed objects. For the User class you can see in the previous example mentioned above.



public class UnzipObjectDemo {
    public static void main(String[] args) {
        File file = new File("user.dat");
        try (FileInputStream fis = new FileInputStream(file);
             GZIPInputStream gis = new GZIPInputStream(fis);
             ObjectInputStream ois = new ObjectInputStream(gis)) {

            User admin = (User) ois.readObject();
            User foo = (User) ois.readObject();

            System.out.println("Admin = [" + admin + "]");
            System.out.println("Foo = [" + foo + "]");
        } catch (IOException | ClassNotFoundException e) {

Running the code snippet above will give us the following output:

Admin = [User{id=1, username='admin', password='secret', firstName='System', lastName='Administrator'}]
Foo = [User{id=2, username='foo', password='secret', firstName='Foo', lastName='Bar'}]

Wayan Saryada

Founder at Kode Java Org
I am a programmer, a runner, a recreational diver, currently live in the island of Bali, Indonesia. Mostly programming in Java, Spring Framework, Hibernate / JPA. If these posts help, you can support me, buy me a cup of coffee or tea. Thank you 🥳

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.