Read/Write Java Object to a File

In Java object can be read or written to a file using serialization and deserialization.

import java.io.*;

public class ObjectFileExample {

    public static void main(String[] args) {
        // Create an object to write to file
        User objectToWrite = new User("Mike", 32);

        // Write object to file
        writeObjectToFile(objectToWrite, "object.txt");

        // Read object from file
        User objectFromFile = readObjectFromFile("object.txt");
        System.out.println(STR."Object read from file: \{objectFromFile}");
    }

    // Method to write object to file
    public static void writeObjectToFile(Object obj, String fileName) {
        try (ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream(fileName))) {
            oos.writeObject(obj);
            System.out.println("Object successfully written to file.");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    // Method to read object from file
    public static User readObjectFromFile(String fileName) {
        try (ObjectInputStream ois = new ObjectInputStream(new FileInputStream(fileName))) {
            return (User) ois.readObject();
        } catch (IOException | ClassNotFoundException e) {
            e.printStackTrace();
            return null;
        }
    }
}


class User implements Serializable {
    private String name;
    private int age;

    public User(String name, int age) {
        this.name = name;
        this.age = age;
    }

    @Override
    public String toString() {
        return STR."User {name='\{name}\{'\''}, age=\{age}\{'}'}";
    }
}

Human-Written Content: This article was demonstrated by a human, not AI.

Please support independent contributors like Code2care by donating a coffee.

References:

• ObjectOutputStream - Documentation for writing objects to an OutputStream.
• ObjectInputStream - Documentation for reading objects from an InputStream.
• Serializable Interface - Documentation for the Serializable interface.