如何访问另一个类

Question

我正在创建一个简单的JavaFX程序，通过将参数从一个阶段传递到另一个阶段来显示警告框/窗口。下面给出了我的Main类，Controller类，AlertBox类及其所有FXML代码的代码。我只想在display类中使用两个参数 - 标题和消息来调用AlertBox函数（在Controller中定义）。我使用Scene Builder来构建程序的UI，但是在AlertBox类中，我无法在显示功能中使用标签和按钮。我收到了这个错误：
Non-static method 'mess' cannot be referenced from static context
有人请告诉我如何解决它，以便我可以在各阶段之间进行沟通。

Main.java

package sample;

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

public class Main extends Application {

    @Override
    public void start(Stage primaryStage) throws Exception{
        Parent root = FXMLLoader.load(getClass().getResource("sample.fxml"));
        primaryStage.setTitle("Hello World");
        primaryStage.setScene(new Scene(root));
        primaryStage.show();
    }


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

sample.fxml

    <?xml version="1.0" encoding="UTF-8"?>

<?import javafx.scene.control.Button?>
<?import javafx.scene.control.CheckBox?>
<?import javafx.scene.control.Label?>
<?import javafx.scene.layout.AnchorPane?>

<AnchorPane maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" prefHeight="400.0" prefWidth="600.0" xmlns="http://javafx.com/javafx/9" xmlns:fx="http://javafx.com/fxml/1" fx:controller="sample.Controller">
   <children>
      <Button fx:id="button" layoutX="274.0" layoutY="188.0" mnemonicParsing="false" text="Go to Scene 2" />
      <Label fx:id="label" layoutX="279.0" layoutY="236.0" style="-fx-background-color: #eee;" text="This is Scene 1!" />
      <CheckBox layoutX="156.0" layoutY="86.0" mnemonicParsing="false" text="CheckBox" />
      <Button fx:id="alert" layoutX="274.0" layoutY="295.0" mnemonicParsing="false" text="Open Alert" />
   </children>
</AnchorPane>

Controller.java

    package sample;

import sample.AlertBox;
import java.io.IOException;
import java.net.URL;
import java.util.ResourceBundle;
import javafx.fxml.FXML;
import javafx.fxml.FXMLLoader;
import javafx.fxml.Initializable;
import javafx.scene.Parent;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.stage.*;
import javafx.scene.*;

public class Controller implements Initializable{

    @FXML
    Label label;
    @FXML Button alert;

    @Override
    public void initialize(URL url, ResourceBundle rb){

        alert.setOnAction(even ->
                {
                    AlertBox.display("Title", "This is the message");
                }

        );


    }

}

AlertBox.java

    package sample;


import javafx.fxml.FXML;
import javafx.fxml.FXMLLoader;
import javafx.fxml.Initializable;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.layout.AnchorPane;
import javafx.stage.Modality;
import javafx.stage.Stage;
import java.io.IOException;
import java.net.URL;
import java.util.ResourceBundle;

public class AlertBox implements Initializable{
    @FXML Button winClose;
    @FXML Label mess;
    @FXML AnchorPane lay;


    @FXML
    public static void display(String title, String message){
        Stage window = new Stage();
        window.initModality(Modality.APPLICATION_MODAL);
        window.setTitle(title);
        mess.setText(message);
        winClose.setOnAction(e -> window.close());

            window.setScene(new Scene(lay));
            window.showAndWait();
 }


    @Override
    public void initialize(URL location, ResourceBundle resources) {}
}

AlertBox.fxml

    <?xml version="1.0" encoding="UTF-8"?>

<?import javafx.scene.control.Button?>
<?import javafx.scene.control.Label?>
<?import javafx.scene.layout.AnchorPane?>


<AnchorPane fx:id="lay" minHeight="250.0" minWidth="250.0" xmlns="http://javafx.com/javafx/9" xmlns:fx="http://javafx.com/fxml/1" fx:controller="sample.AlertBox">
   <children>
      <Button fx:id="winClose" layoutX="69.0" layoutY="179.0" mnemonicParsing="false" text="Close the Window" />
      <Label fx:id="mess" layoutX="109.0" layoutY="120.0" prefHeight="17.0" prefWidth="68.0" />
   </children>
</AnchorPane>