序列化无法在我的JFrame中使用

Question

我不确定为什么用户没有将这些专辑序列化。 在admin类中，当我登录时，每次重新启动程序时userlist都会填充JCombobox<String> userlist。 但是每次重新启动程序时都不会填充JComboBox<Album> comboBoxAlbumSelect。 不知道为什么。感谢。

相关代码：

public class Admin extends JFrame implements ActionListener {
Backend backend = new Backend();
GuiCtrl ctrl = new GuiCtrl(backend);
private JComboBox<String> userlist = new JComboBox<String>();

    public Admin() {
    //same as login
    userlist = new JComboBox<String>(getUserList());
}

public String[] getUserList() {
    String[] ret = new String[backend.getUserList().size()];
    int i = 0;
    for (String s : backend.getUserList()) {
        System.out.println(s);
        ret[i++] = s;
    }
    return ret;
}

public void actionPerformed(ActionEvent e) {
    if (e.getSource() == logout) {
        this.dispose();
        new Login();
    }
    else if (e.getSource() == add) {
        try {
        if (ctrl.adduser(idNumberTF.getText(), fullNameTF.getText())) {
            userlist.addItem(idNumberTF.getText());
            backend.storeData();
        } catch (IOException|ClassNotFoundException i) {}
    }
}
}

• public class MainAlbumPanelv2 extends JFrame implements ActionListener {
  JButton btnCreateAlbum = new JButton("Create");
  JComboBox<Album> comboBoxAlbumSelect = new JComboBox<Album>();
  Backend backend = new Backend();
  GuiCtrl ctrl = new GuiCtrl(backend);
  User loggedInUser;
  
  public MainAlbumPanelv2(User id) {
      loggedInUser = id;
      comboBoxAlbumSelect = new JComboBox<Album>(getAlbumList());
  }
  
  public void actionPerformed(ActionEvent e) {
      if (e.getSource() == btnCreateAlbum) {
          if (ctrl.createAlbum(loggedInUser, textFieldCreateAlbum.getText())) {
          Album newAlbum = new Album(textFieldCreateAlbum.getText());
          comboBoxAlbumSelect.addItem(newAlbum);
          }
          try {
          backend.storeData();
          } catch (IOException i) {}
      }
  }
  
  public Album[] getAlbumList() {
      Album[] ret = new Album[loggedInUser.getAlbums().size()];
      int i = 0;
      for (Album a : loggedInUser.getAlbums()) {
          System.out.println(a);
          ret[i++] = a;
      }
      return ret;
  }
  }
  

-

public class GuiCtrl {
User loggedInUser;
Backend backend;

    public GuiCtrl(Backend backend) {
        this.backend = backend;
    }

    public boolean adduser(String user_id, String user_name) throws IOException, ClassNotFoundException {
        if (backend.addUser(new User(user_id, user_name))) {
            return true;
        } else {
            return false;
        }
    }

    public boolean createAlbum(User user_id, String name) {
        if (user_id.getAlbum(name) != null) {
            return false;
        } else {
            user_id.addAlbum(name);
            return true;
        }
    }
}

-

public class Backend {
    private HashMap<String, User> userList = new HashMap<>();
    StringTokenizer tokenizer;

    public Backend() {
        try {
            populateList();
        } catch (ClassNotFoundException | IOException e) {
            throw new RuntimeException("Cannot read file");
        }
    }

    public boolean addUser(User newUser)
    {
        String userId = newUser.getID();
        if (userList.containsKey(userId)) {
            return false;
        }
        userList.put(userId, newUser);
        return true;
    }

    public void storeData() throws IOException
    {
        try
        {
            FileOutputStream file = new FileOutputStream("users.ser");
            ObjectOutputStream out = new ObjectOutputStream(file);
            out.writeObject(userList);
            out.close();
            file.close();
        }
        catch (IOException i)
        {
            i.printStackTrace();
        }
    }

    public void populateList() throws IOException, ClassNotFoundException
    {
        try
        {
            FileInputStream file = new FileInputStream ("users.ser");
            ObjectInputStream in = new ObjectInputStream(file);
            userList = (HashMap<String, User>) in.readObject();
            in.close();
            file.close();
        }
        catch (IOException i)
        {
            i.printStackTrace();
            userList = new HashMap();
        }
    }
}

• public class Album implements Serializable{
  private String name;
  private ArrayList<Photo> photoList;
  
  
  public Album(String name)
  {
      this.name = name;
      photoList = new ArrayList<Photo>();
  }
  }
  
  public class User implements Serializable{
  private String id;
  private String fullName;
  private ArrayList<Album> albumList;
  public User(String id, String fullName)
  {
      this.id = id;
      this.fullName = fullName;
      albumList = new ArrayList<Album>();
  }
  public int addAlbum(Album newAlbum)
  {
      Album currAlbum;
      if (newAlbum == null)
      {
          return 0;
      }
      for (int x = 0; x < albumList.size(); x++)
      {
          currAlbum = albumList.get(x);
          if (currAlbum.getName().equals(newAlbum.getName()))
          {
              return 0;
          }
      }
      albumList.add(newAlbum);
      return 1;
  }
  public ArrayList<Album> getAlbums()
  {
      return albumList;
  }
  }