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如何实现可序列化以使我的项目具有持久性?

observablelist serializable javafx serialization java

-1

Daniel · 技术社区 · 7 年前

public class ToDoList extends Application{

public static void main(String[] args) {
    launch(args);
}

public void start(Stage primaryStage) throws Exception {

    Pane pane = FXMLLoader.load(getClass().getResource("ToDoList.fxml"));

    Scene scene = new Scene(pane);
    scene.getStylesheets().add(getClass().getResource("ToDoListStyle.css").toExternalForm());
    primaryStage.setScene(scene);
    primaryStage.setTitle("Plan yourself");
    primaryStage.show();
}

}

然后控制器的一部分:

    ObservableList<EventsBean> dataList = FXCollections.observableArrayList();

@Override
public void initialize(URL location, ResourceBundle resources) {
    System.out.println("The pane loaded");

    List<String> myList;
    try {
        myList = Files.lines(Paths.get("src/com/todolist/EventsList.txt")).collect(Collectors.toList());
        eventsSelector.setItems(FXCollections.observableArrayList(myList));
    } catch (IOException e) {
        System.out.println("Don t find file");
    }

    removeCol.setCellFactory(CheckBoxTableCell.forTableColumn(removeCol));
    eventCol.setCellValueFactory(new PropertyValueFactory<EventsBean, String>("event"));
    dateCol.setCellValueFactory(new PropertyValueFactory<EventsBean, LocalDate>("date"));
    doneCol.setCellValueFactory(new PropertyValueFactory<EventsBean, String>("done"));
    doneCol.setCellFactory(TextFieldTableCell.<EventsBean>forTableColumn());
    doneCol.setOnEditCommit((CellEditEvent<EventsBean, String> t) -> {
        ((EventsBean) t.getTableView().getItems().get(t.getTablePosition().getRow()))
                .setDone(t.getNewValue());
    });
    observationCol.setCellValueFactory(new PropertyValueFactory<EventsBean, String>("observation"));
    removeCol.setCellValueFactory(cellData -> cellData.getValue().selectedProperty());
    observationCol.setCellFactory(TextFieldTableCell.<EventsBean>forTableColumn());
    observationCol.setOnEditCommit((CellEditEvent<EventsBean, String> t) -> {
        ((EventsBean) t.getTableView().getItems().get(t.getTablePosition().getRow()))
                .setObservation(t.getNewValue());
    });
    observationCol.setSortable(false);

    eventsTable.setItems(dataList);
    eventsTable.setEditable(true);

    bttnAddEvent.setOnAction((ActionEvent e) -> {
        try {
            text = eventsSelector.getValue().toString();
            dataList.add(new EventsBean(text, isoDate, "",  "", false));
        } catch (Exception e1) {
            System.out.println("Nothing selected");
        }
    });

    bttnRemove.setOnAction((ActionEvent e) -> {
        ObservableList<EventsBean> dataListToRemove = FXCollections.observableArrayList();
        for (EventsBean bean : dataList) {
            if (bean.getSelected()) {
                dataListToRemove.add(bean);
            }
        }
        dataList.removeAll(dataListToRemove);

        // Below code it is for delete a focused row
        // EventsBean selectedItem = eventsTable.getSelectionModel().getSelectedItem();
        // eventsTable.getItems().remove(selectedItem);
    });

}

然后事件bean:

public class EventsBean {


private SimpleStringProperty event;
private SimpleObjectProperty<LocalDate> date;
private SimpleStringProperty done;
private SimpleStringProperty observation;
private SimpleBooleanProperty selected;

public EventsBean(String event, LocalDate date, String done, String observation, boolean selected) {
    this.event = new SimpleStringProperty(event);
    this.date = new SimpleObjectProperty<LocalDate>(date);
    this.done = new SimpleStringProperty(done);
    this.observation = new SimpleStringProperty(observation);
    this.selected = new SimpleBooleanProperty(selected);
}
// Getters and Setters ...

我想序列化表中的数据。我认为可序列化对象是ObservableList中的dataList。我的问题是在哪里实现可序列化接口?对于我来说,这是持久性的最佳解决方案?

1 回复 | 直到 7 年前

1

0

James_D 7 年前

您应该首先问问自己是否真的想在这里使用对象序列化。最好使用不同的持久性方法:例如,使用JSON封送库,例如 GSON 。大多数这样的库只使用对象的 get 和 set EventsBean 使用很少的额外代码初始化。

事件bean 班 Serializable 。通常这很简单,但您将遇到的问题是JavaFX属性类没有实现真是太天真了使生效尝试序列化它的实例将生成运行时异常。要做到这一点,需要使用自定义序列化。

首先,创建JavaFX属性 transient readObject 和 writeObject 定义对象应如何序列化的方法:

public class EventsBean implements Serializable {


    private transient SimpleStringProperty event;
    private transient SimpleObjectProperty<LocalDate> date;
    private transient SimpleStringProperty done;
    private transient SimpleStringProperty observation;
    private transient SimpleBooleanProperty selected;

    // constructors...

    // example get/set/property methods:
    public StringProperty eventProperty() {
        return event ;
    }

    public final String getEvent() {
        return eventProperty().get();
    }

    public final void setEvent(String event) {
        eventProperty().set(event);
    }

    // etc. for other properties...


    // custom serialization:
    private void writeObject(ObjectOutputStream s) throws IOException {
        s.defaultWriteObject();
        s.writeObject(getEvent()); // write event as a plain String
        s.writeObject(getDate()); 
        s.writeObject(getDone());
        s.writeObject(getObservation());
        s.writeBoolean(isSelected());
    }

    // custom deserialization:
    private void readObject(ObjectInputStream s) throws IOException {
        s.defaultReadObject();
        this.event = new SimpleStringProperty((String)s.readObject());
        this.data = new SimpleObjectProperty<>((LocalDate)s.readObject());
        this.done = new SimpleStringProperty((String)s.readObject());
        this.observation = new SimpleStringProperty((String)s.readObject());
        this.selected = new SimpleBooleanProperty(s.readBoolean());
    }
}

ObservableList 实现通常不可序列化,因此需要序列化“常规”列表以序列化数据,即:

ObjectOutputStream s = ... ;
s.writeObject(new ArrayList<EventsBean>(dataList));

回过头来看:

ObjectInputStream s = ... ;
dataList.setAll((List<EventsBean>)s.readObject());