java - 使用不可序列化的对象序列化 hashmap

Question

如何序列化包含不可序列化对象的散列图，在我的例子中是 JavaFX 组件？

final HashMap<String, Button> mapButton = new HashMap<>();
// some for loop adding the components..
try {
     FileOutputStream fileOut = new FileOutputStream("Resources/");
     ObjectOutputStream objStream = new ObjectOutputStream(fileOut);
     objStream.writeObject(mapButton);
     objStream.close();
     fileOut.close();
     System.out.println("Serialized HashMap mapButtons has been stored"
                         + " in /tmp/store");
    } catch (IOException i) {
          i.printStackTrace();
    }

抛出:

java.io.NotSerializableException: javafx.scene.control.Button

Answer 1

如果你想序列化对象，那么它们必须是Serializable。

由于 javafx.scene.control.Button 不可序列化，您必须找到另一种方法将按钮的状态保存在其他地方。例如。通过引入一个保护状态的纪念类:

public class ButtonMemento implements Serializable {

       private static final long serialVersionUID = 1L;

       private boolean text;

       /*
        * Creates a memento that safes the given button's current state.
        */
       public ButtonMemento(Button button){
             this.text = button.getText();
            // extend to record more properties of the button
       }

       /*
        * Used to apply the current mementos state to a button
        */
       public void applyState(Button button){
           button.setText(text);
           // extend to apply more properties to the button
       }
}

ButtonMemento 类是一种保护不可序列化对象的状态并在以后恢复它的方法。

final HashMap<String, ButtonMemento> mapButton = new HashMap<>();

for(Button b : buttons){
    String mapKey = ...;
    mapButton.put(mapKey, new ButtonMemento(b));
}    

try {
    FileOutputStream fileOut = new FileOutputStream("Resources/");
    ObjectOutputStream objStream = new ObjectOutputStream(fileOut);
    objStream.writeObject(mapButton);
    objStream.close();
    fileOut.close();
    System.out.println("Serialized HashMap mapButtons has been stored"
                     + " in /tmp/store");
} catch (IOException i) {
      i.printStackTrace();
}

也许您可以实现类似 BeanMemento 的东西，它可以存储可序列化的 bean 的属性，因此可以与满足 java bean 规范的每个对象一起使用。