File with users choices containing different objects

Question

I am making a simple application in Java (Animal shelter), it allows you to add animals to the list, edit free places, send email when the free space ends and all the changes are saved when the program closes and loaded after it is turned on.

However, the list of animals (ArrayList) is saved in one file, a list of free places in the second, email address (string) in the third, etc. ...
I have tried to place objects that need to be saved in one collection (ArrayList ), but this file does not load correctly.

Any ideas how to save and read different types in a txt file?

Example of my import/export class:

 void autoSave() {

    try {
        FileOutputStream fout = new FileOutputStream(path);
        ObjectOutputStream oos = new ObjectOutputStream(fout);
        oos.writeObject(AddAnimalScene.listOfAnimals);
        oos.close();

        FileOutputStream fout1 = new FileOutputStream(path1);
        ObjectOutputStream oos1 = new ObjectOutputStream(fout1);
        oos1.writeObject(EditFreeSpaceScene.places);
        oos1.close();

    } catch (IOException e) {
        e.printStackTrace();
    }
}


void autoLoad() {
    try {
        ObjectInputStream in = new ObjectInputStream(new FileInputStream(path));
        ArrayList<Animal> LoadedAnimalList = (ArrayList<Animal>) in.readObject();
        in.close();
        AddAnimalScene.listOfAnimals = LoadedAnimalList;

        ObjectInputStream in1 = new ObjectInputStream(new FileInputStream(path1));
        Integer LoadedPlaces = (Integer) in1.readObject();
        in1.close();
        EditFreeSpaceScene.places = LoadedPlaces;

    } catch (IOException | ClassNotFoundException e) {
        e.printStackTrace();
    }
}

Saying **but this file does not load correctly** is not enough. Provide specifics of issue. — Sabir Khan, Apr 18 '17 at 12:02
why are you saving in text files? it's not practical. Maybe you should consider using a database connection. — Elie Nassif, Apr 18 '17 at 12:02
@Jens It's " static int places = 20;" - number of total space in shelter. — Marta.Paula, Apr 18 '17 at 12:08
@SabirKhan There is no error or exception, it's just not loading as when everything is in separate files. — Marta.Paula, Apr 18 '17 at 12:08
@ElieNassif I am beginner, using stuff like Hibernate will be my next step :) — Marta.Paula, Apr 18 '17 at 12:08
please provide an [mvce] so we can copy and paste it and try by our self — Jens, Apr 18 '17 at 12:10
Possible duplicate of [Java - How Can I Write My ArrayList to a file, and Read (load) that file to the original ArrayList?](http://stackoverflow.com/questions/16111496/java-how-can-i-write-my-arraylist-to-a-file-and-read-load-that-file-to-the) — Viktor Mellgren, Apr 18 '17 at 12:16
Have you implemented Serializable interface in your classes that need to be kept in ArrayList and then need to be written in file. — Anil Agrawal, Apr 18 '17 at 12:18

Dimitar · Answer 1 · 2017-04-18T12:23:21.613

A tip: Always read the Javadoc, especially as a beginner. Might be challenging at first, but it will pay off later. In my opinion, consulting the official documentation is always the right way to clear any issues.

From the ObjectOutputStream Javadoc:

Only objects that support the java.io.Serializable interface can be written to streams.

Your Animal class should implement Serializable interface.

On the other hand, if you want to explicitly specify a field should not be serialized, you could use the transient modifier.

File with users choices containing different objects

1 Answers1