用Java在文件中加载/存储对象 [英] Load/Store Objects in file in Java

问题描述

我想将类中的对象存储在文件中，然后再从该文件中加载对象.但是在某个地方我犯了一个错误，无法弄清楚在哪里.我可以帮忙吗?

I want to store an object from my class in file, and after that to be able to load the object from this file. But somewhere I am making a mistake(s) and cannot figure out where. May I receive some help?

public class GameManagerSystem implements GameManager, Serializable {

    private static final long serialVersionUID = -5966618586666474164L;
    HashMap<Game, GameStatus> games;
    HashMap<Ticket, ArrayList<Object>> baggage;
    HashSet<Ticket> bookedTickets;
    Place place;


    public GameManagerSystem(Place place) {
        super();

        this.games = new HashMap<Game, GameStatus>();
        this.baggage = new HashMap<Ticket, ArrayList<Object>>();
        this.bookedTickets = new HashSet<Ticket>();
        this.place = place;
    }
    public static GameManager createManagerSystem(Game at) {
        return new GameManagerSystem(at);
    }

    public boolean store(File f) {
        try {
            FileOutputStream fos = new FileOutputStream(f);
            ObjectOutputStream oos = new ObjectOutputStream(fos);
            oos.writeObject(games);
            oos.writeObject(bookedTickets);
            oos.writeObject(baggage);
            oos.close();
            fos.close();
        } catch (IOException ex) {
            return false;
        }
        return true;
    }
    public boolean load(File f) {
        try {
            FileInputStream fis = new FileInputStream(f);
            ObjectInputStream ois = new ObjectInputStream(fis);
            this.games = (HashMap<Game,GameStatus>)ois.readObject();
            this.bookedTickets = (HashSet<Ticket>)ois.readObject();
                this.baggage = (HashMap<Ticket,ArrayList<Object>>)ois.readObject();
            ois.close();
            fis.close();
        } catch (IOException e) {
            return false;
        } catch (ClassNotFoundException e) {
            return false;
        }
        return true;
    }
.
.
.
}


public class JUnitDemo {

    GameManager manager;

    @Before
    public void setUp() {
        manager = GameManagerSystem.createManagerSystem(Place.ENG);
    }

    @Test
    public void testStore() {
        Game g = new Game(new Date(), Teams.LIONS, Teams.SHARKS);
        manager.registerGame(g);
        File file = new File("file.ser");
        assertTrue(airport.store(file));
    }
}

推荐答案

此问题的解决方案是，当您使用其他对象时，将类 A 放入类似的集合中HashMap ，并想序列化 HashMap 对象，然后为类 A 的 Serializable 接口实现 implement 这个:

The solution of this problem is that when you are using other objects, let say class A, into a collection like HashMap and want to serialize the HashMap object, then implement the interface Serializable for class A like this:

class A implements Serializable {
}

...
    HashMap<Integer,A> hmap;
...

否则该对象将无法序列化.

Otherwise that object will not be serializable.

我希望它现在能解决这个问题.

I hope it will solve this problem now.

这篇关于用Java在文件中加载/存储对象的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！