反序列化多个Java对象

Z时代
2024-01-10
分类：问答

你好亲爱的同事们，

我有一个Garden类，在其中我可以序列化和反序列化多个Plant类对象。如果想将其分配给mein静态方法中的调用变量，则可以进行序列化，但是不能进行反序列化。

public void searilizePlant(ArrayList<Plant> _plants) {
    try {
        FileOutputStream fileOut = new FileOutputStream(fileName);
        ObjectOutputStream out = new ObjectOutputStream(fileOut);
        for (int i = 0; i < _plants.size(); i++) {
            out.writeObject(_plants.get(i));
        }
        out.close();
        fileOut.close();
    } catch (IOException ex) {
    }
}

反序列化代码：

public ArrayList<Plant> desearilizePlant() {
    ArrayList<Plant> plants = new ArrayList<Plant>();
    Plant _plant = null;
    try {
        ObjectInputStream in = new ObjectInputStream(new FileInputStream(fileName));
        Object object = in.readObject();
       // _plant = (Plant) object;
        // TODO: ITERATE OVER THE WHOLE STREAM
        while (object != null) {
            plants.add((Plant) object);
            object = in.readObject();
        }
        in.close();
    } catch (IOException i) {
        return null;
    } catch (ClassNotFoundException c) {
        System.out.println("Employee class not found");
        return null;
    }
    return plants;
}

我的调用代码：

ArrayList<Plant> plants = new ArrayList<Plant>();
plants.add(plant1);
Garden garden = new Garden();
garden.searilizePlant(plants);
// THIS IS THE PROBLEM HERE
ArrayList<Plant> dp = new ArrayList<Plant>();
dp = garden.desearilizePlant();

我有一个空的Pointer异常

@NilsH的解决方案工作正常，谢谢！

回答：

如何序列化整个列表呢？无需序列化列表中的每个对象。

public void searilizePlant(ArrayList<Plant> _plants) {
    try {
        FileOutputStream fileOut = new FileOutputStream(fileName);
        ObjectOutputStream out = new ObjectOutputStream(fileOut);
        out.writeObject(_plants);
        out.close();
        fileOut.close();
    } catch (IOException ex) {
    }
}
public List<Plant> deserializePlant() {
    List<Plants> plants = null;
    try {
        ObjectInputStream in = new ObjectInputStream(new FileInputStream(fileName));
        plants = in.readObject(); 
        in.close();
    }
    catch(Exception e) {}
    return plants;
}