使用Jackson Databind序列化对象时出现Java InvalidDefinitionException

Question

我正在尝试使用Jackson的ObjectMapper将以下Player对象写为String。

package models.Game;

import models.Game.Enums.SnowballState;
import javafx.scene.paint.Color;
import javafx.scene.shape.Circle;

import java.util.ArrayList;
import java.util.List;

public class Player {
    private Circle circle;
    private String name;
    private Color color;
    private int points = 0;
public int getLives() {
    return lives;
}

private int lives = 3;
private List<Snowball> snowballs;
private Circle oldCircle;
private int stepSize = 10;

public Player(String name, Color color) {
    this.name = name;
    circle = new Circle();
    oldCircle = new Circle();
    this.color = color;
    snowballs = new ArrayList<>();
    snowballs.add(new Snowball(this));
    snowballs.add(new Snowball(this));
    snowballs.add(new Snowball(this));
}

public Player() {

}

private void removeLife() {
    this.lives--;
}

public int getHit() {
    removeLife();
    return getLives();
}

public int shotSuccess() {
    points+= 50;
    return points;
}

public int getSnowballAmount() {
    int balls = 0;
    for (Snowball ball : snowballs) {
        if (ball.getState() == SnowballState.CREATED) {
            balls++;
        }
    }
    return balls;
}

public List<Snowball> getSnowballs() {
    return snowballs;
}

public Snowball getNextSnowball() {
    for (Snowball ball : snowballs) {
        if (ball.getState() == SnowballState.CREATED) {
            return ball;
        }
    }
    return null;
}

public void createSnowball() {
    if (getSnowballAmount() < 3) {
        snowballs.add(new Snowball(this));
    }
}

public Color getColor() {
    return this.color;
}

public Circle getCircle() {
    return this.circle;
}

public void moveLeft() {
    saveOld();
    circle.setTranslateX(circle.getTranslateX() - stepSize);
}

public void moveRight() {
    saveOld();
    circle.setTranslateX(circle.getTranslateX() + stepSize);
}

public void moveUp() {
    saveOld();
    circle.setTranslateY(circle.getTranslateY() - stepSize);
}

public void moveDown() {
    saveOld();
    circle.setTranslateY(circle.getTranslateY() + stepSize);
}

public void undo() {
    circle.setTranslateX(oldCircle.getTranslateX());
    circle.setTranslateY(oldCircle.getTranslateY());
}

private void saveOld() {
    oldCircle.setTranslateX(circle.getTranslateX());
    oldCircle.setTranslateY(circle.getTranslateY());
}

public Snowball shootSnowball(Snowball ball, double mouseX, double mouseY) {

    double polarDirection = Math.atan2(mouseY - circle.getTranslateY(), mouseX - circle.getTranslateX() + 50);
    ball.setState(SnowballState.ALIVE);
    ball.setDirection(polarDirection);
    ball.getCircle().setTranslateX(circle.getTranslateX() + 50);
    ball.getCircle().setTranslateY(circle.getTranslateY());
    return ball;
}

我正在使用以下命令来执行此操作：

 String json = null;
        try {
            json = objectMapper.writeValueAsString(instanceOfPlayerClass);
        } catch (JsonProcessingException e) {
            e.printStackTrace();
        }

不幸的是，我收到以下相关错误消息：

com.fasterxml.jackson.databind.exc.InvalidDefinitionException：类型的无效类型定义com.sun.javafx.scene.NodeEventDispatcher：无法为[简单类型，类com.sun.javafx.scene.NodeEventDispatcher]构造BeanSerializer：（java.lang.reflect.InaccessibleObjectException）使最终的最终com.sun.javafx.event.BasicEventDispatcher公开。com.sun.javafx.event.BasicEventDispatcher.getPreviousDispatcher（）可访问：模块javafx.base不会将com.sun.javafx.event导出到模块com.fasterxml.jackson .databind（通过参考链：models.communication.Websockets.ConnectionSubmitModel [“ player”]-> models.Game.Player [“ circle”]-> javafx.scene.shape.Circle [“ parent”]-> javafx.scene .layout.GridPane [“ parent”]-> javafx.scene.layout.AnchorPane [“ eventDispatcher”]）

就像错误所说的那样，这与JavaFx没有导出特定的依赖关系有关，但是由于我不受JavaFx的控制，因此我不确定如何解决此问题。

Answer 1

您试图存储该类Circle，它是一个 JavaFX 类，实际上并不是一个数据类（它是一个 UI 元素），具有许多属性（如半径、厚度、颜色、填充、边框等）。因此，它以各种方式与 JavaFX 系统捆绑在一起，并且不能很好地存储。

相反，只需将所需的信息存储在您自己的一个简单的类中，该类包含您Circle读回时再次创建对象所需的信息。