Java如何序列化包含子类的List <superclass>？

Question

我喜欢序列化一个列表，当它保存时，它确实包含列表中某个元素是Child 的信息，但是当我尝试读取它时，它返回一个未初始化的信息父类

public static List<Parent> myList = new ArrayList<Parent>();
ds = new Child(3, 4, 3, "zh", "hj" , "ni", p);
myList.add(ds);

try {
        logToFile(myList, saveTo);                 //My method for saving
    } catch (URISyntaxException e) {
        e.printStackTrace();
    }

myList = (List<Parent>) readFromFile(saveTo); //My method for reading
//My list containing null for each Child

我可能还应该包括Parent是抽象类并扩展第三方类

修改 这是我的保存和阅读功能

    public void logToFile(Object o, File f) throws URISyntaxException

    {

        try
        {
            FileOutputStream fout = new FileOutputStream(f);
            ObjectOutputStream oos = new ObjectOutputStream(fout);
            oos.writeObject(o);
            oos.close();

        } catch (IOException e)
        {

            e.printStackTrace();

        }

    }


        public Object readFromFile(File f) throws ClassNotFoundException, IOException {

        FileInputStream is = new FileInputStream(f);
        ObjectInputStream g = new ObjectInputStream(is);

        Object oggg = g.readObject();

        g.close();
        return oggg;


    }

家长和孩子的班级

 public class Child extends Parent implements java.io.Serializable{


/**
 * 
 */
private static final long serialVersionUID = -8270915411149374357L;

public Child(int x, int z, int y, Material m, String Title) {
    super(m, Title);
    this.x = x;
    this.y = y;
    this.z = z;
}


public abstract class Parent extends ItemStack implements java.io.Serializable{

// ItemStack是第三方类

/**
 * 
 */
private static final long serialVersionUID = -904093000933705904L;

public Parent(Material M, String name) {
    super(M);
    setName(name);
}

程序生成的文本文件的短片段：