如何正确地将我的自定义类导入此FXML文件？

// CustomClass.java
package com.example;

public class CustomClass {
    // 自定义类的属性和方法
}

// SampleController.java
package com.example;

public class SampleController {
    // 控制器类的代码
}

<!-- Sample.fxml -->
<?xml version="1.0" encoding="UTF-8"?>

<?import javafx.scene.control.Button?>
<?import javafx.scene.layout.AnchorPane?>
<?import com.example.CustomClass?>

<AnchorPane xmlns:fx="http://javafx.com/fxml" fx:controller="com.example.SampleController">
    <!-- 在这里使用自定义类 -->
    <Button text="Click" customClassProperty="CustomClassInstance"/>
</AnchorPane>

// Main.java
package com.example;

import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Scene;
import javafx.stage.Stage;

public class Main extends Application {
    @Override
    public void start(Stage primaryStage) throws Exception {
        FXMLLoader loader = new FXMLLoader(getClass().getResource("Sample.fxml"));
        loader.load();
        Scene scene = new Scene(loader.getRoot());
        primaryStage.setScene(scene);
        primaryStage.show();
    }

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