财产看似不正常，因为它是一个整数

Question

好的，这是我在游戏中遇到的第二个问题。这是一个基于文本的游戏，我也想根据用户的答案增加点数。我还有另一个课程可以保存游戏和积分，以防用户想要稍后继续游戏。游戏保存正常，但点数没有，我认为这是因为它应该返回一个整数。但我不知道如何解决这个问题。程序甚至没有启动，因为我得到的错误是线程“main”中的异常java.lang.NumberFormatException：java.lang.Integer.parseInt中的null ...提前感谢！

MainGame

public class MainGame {

    public static GameSave gameSave = new GameSave();
    public static String user = "";
    public static Scanner scanner = new Scanner(System.in);
    public static String question;
    public static int relationshipPoints;

    public static void main(String[] args) {
        Random random = new Random();
        question = gameSave.loadGame();
        relationshipPoints = gameSave.loadPoints();
        RelationshipPoints points = new RelationshipPoints();

        System.out.println("\n\t*** TEXT_GAME: FIRSTDATE ***\n");
        System.out.println("-You can exit the game at any time by typing 'exit'.-\n\n");

        while (true) {
            user = scanner.nextLine();

            switch (question) {
                case "4_Story2":
                if (user.trim().equalsIgnoreCase("exit")) {
                    System.exit(1);
                    break;
                }
                switch (user) {
                case "1":
                    System.out.println("\n\nIan is overjoyed!");
                    relationshipPoints++;
                    gameSave.savePoints(relationshipPoints);
                    gameSave.saveGame("4B");
                    question = "4B";
                    break;
                case "2": [...]

GameSave

public class GameSave {

    public static Properties prop = new Properties();

    public void savePoints(int points) {
        try {
            prop.setProperty("Save_RPS", String.valueOf(points));
            prop.store(new FileOutputStream("config.prop"), null);
        } catch (IOException e) {

        }
    }

    public void saveGame(String point) {
        try {
            prop.setProperty("Save_Point", point);
            prop.store(new FileOutputStream("config.prop"), null);
        } catch (IOException e) {

        }
    }

    public int loadPoints() {
        int p = 0;
        String line = "";
        try {
            prop.load(new FileInputStream("config.prop"));
            line = prop.getProperty("Save_RPS");
        } catch (IOException e) {
            try {
                prop.setProperty("Save_RPS", String.valueOf(p));
                prop.store(new FileOutputStream("config.prop"), null);

                try {
                    prop.load(new FileInputStream("config.prop"));
                    line = prop.getProperty("Save_RPS");
                } catch (IOException exe) {

                }
            } catch (IOException ex) {

            }
        }
        p = Integer.parseInt(line);
        return p;
    }

    public String loadGame() {
        String line = "";
        try {
            prop.load(new FileInputStream("config.prop"));
            line = prop.getProperty("Save_Point");
        } catch (IOException e) {
            try {
                prop.setProperty("Save_Point", "0");
                prop.store(new FileOutputStream("config.prop"), null);

                try {
                    prop.load(new FileInputStream("config.prop"));
                    line = prop.getProperty("Save_Point");
                } catch (IOException exe) {

                }

            } catch (IOException ex) {

            }
        }
        return line;
    }

    public void newGame() {
        try {
            prop.setProperty("Save_Point", "0");
            prop.store(new FileOutputStream("config.prop"), null);
        } catch (IOException e) {

        }
    }
}