Question

I am working on a basic encryption program for a school project, and I want to have easily interchangable keys. As it stands, I have a encryption class and a decryption class, with multiple methods. One of those methods is the key that I want to print to a file. Because I will be making many changes to those two classes (apart from the keys), I want to be able to print just that one method to a file. I also need to be able to load it again. Is there any easy way to do this?

Answer 1

You could use java serialization, as you commented that you have a String array to save, you could do something like this:

// save object to file
ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream(new File("/tmp/file")));
oos.writeObject(myArray); // where myArray is String[]

// load object from file
ObjectInputStream ois = new ObjectInputStream(new FileInputStream(new File("/tmp/file")));
String[] read = (String[]) ois.readObject();

A working example ;), saving the arguments received with the application execution.

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.util.Arrays;

public class TestSerialization {

    public static void main(final String[] array) throws FileNotFoundException, IOException, ClassNotFoundException {
        // save object to file
        ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream(new File("/tmp/file")));
        oos.writeObject(array); // where myArray is String[]

        // load object from file
        ObjectInputStream ois = new ObjectInputStream(new FileInputStream(new File("/tmp/file")));
        String[] read = (String[]) ois.readObject();

        System.out.println(Arrays.toString(read));
    }

}