How do you use customizing serialization (readObject/writeObject) with a simple code example?

Customizing serialization in Java allows you to define exactly how an object is serialized and deserialized. This can be particularly useful when you need to control the process of saving and restoring the state of an object. Below is a simple example demonstrating how to implement the `readObject` and `writeObject` methods to customize the serialization behavior of a class.


    import java.io.*;

    class User implements Serializable {
        private String username;
        private transient String password; // transient fields are not serialized

        public User(String username, String password) {
            this.username = username;
            this.password = password;
        }

        // Custom serialization
        private void writeObject(ObjectOutputStream oos) throws IOException {
            oos.defaultWriteObject(); // default serialization
            oos.writeObject(encryptPassword(password)); // encrypt password
        }

        // Custom deserialization
        private void readObject(ObjectInputStream ois) throws IOException, ClassNotFoundException {
            ois.defaultReadObject(); // default deserialization
            password = decryptPassword((String) ois.readObject()); // decrypt password
        }

        private String encryptPassword(String password) {
            // Simple encryption logic (for demonstration)
            return password.replace("a", "@").replace("e", "3");
        }

        private String decryptPassword(String password) {
            // Simple decryption logic
            return password.replace("@", "a").replace("3", "e");
        }
        
        @Override
        public String toString() {
            return "User{" +
                   "username='" + username + '\'' +
                   ", password='" + password + '\'' +
                   '}';
        }
    }

    public class SerializeExample {
        public static void main(String[] args) {
            User user = new User("john_doe", "myp@ssw0rd");

            // Serialization
            try (ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream("user.dat"))) {
                oos.writeObject(user);
            } catch (IOException e) {
                e.printStackTrace();
            }

            // Deserialization
            try (ObjectInputStream ois = new ObjectInputStream(new FileInputStream("user.dat"))) {
                User deserializedUser = (User) ois.readObject();
                System.out.println(deserializedUser);
            } catch (IOException | ClassNotFoundException e) {
                e.printStackTrace();
            }
        }
    }

How do you use customizing serialization (readObject/writeObject) with a simple code example?

Popular Topics

Recent Languages

How do you use customizing serialization (readObject/writeObject) with a simple code example?

Related Questions

Popular Topics

Recent Languages