如何在GUI应用程序中指定控制器？

如何解决如何在GUI应用程序中指定控制器？

我正在用Java做一个简单的GUI项目。有时它会注意到我的fxml文件并且可以正常运行，但是过了一会儿它选择忽略它，并抛出以下消息：

 Exception in Application start method
java.lang.reflect.InvocationTargetException
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at com.sun.javafx.application.LauncherImpl.launchApplicationWithArgs(LauncherImpl.java:389)
    at com.sun.javafx.application.LauncherImpl.launchApplication(LauncherImpl.java:328)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at sun.launcher.LauncherHelper$FXHelper.main(Unknown Source)
Caused by: java.lang.RuntimeException: Exception in Application start method
    at com.sun.javafx.application.LauncherImpl.launchApplication1(LauncherImpl.java:917)
    at com.sun.javafx.application.LauncherImpl.lambda$launchApplication$1(LauncherImpl.java:182)
    at java.lang.Thread.run(Unknown Source)
Caused by: javafx.fxml.LoadException: No controller specified.
/C:/Users/M%c3%a1t%c3%a9/Desktop/Workspace/KisallatNyilvantartoRendszer/target/classes/main/allatok.fxml:24

    at javafx.fxml.FXMLLoader.constructLoadException(FXMLLoader.java:2597)
    at javafx.fxml.FXMLLoader.access$100(FXMLLoader.java:103)
    at javafx.fxml.FXMLLoader$Element.getControllerMethodHandle(FXMLLoader.java:557)
    at javafx.fxml.FXMLLoader$Element.processEventHandlerAttributes(FXMLLoader.java:599)
    at javafx.fxml.FXMLLoader$ValueElement.processEndElement(FXMLLoader.java:770)
    at javafx.fxml.FXMLLoader.processEndElement(FXMLLoader.java:2823)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2532)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2441)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3214)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3175)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3148)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3124)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3104)
    at javafx.fxml.FXMLLoader.load(FXMLLoader.java:3097)
    at main.Main.start(Main.java:18)
    at com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$8(LauncherImpl.java:863)
    at com.sun.javafx.application.PlatformImpl.lambda$runAndWait$7(PlatformImpl.java:326)
    at com.sun.javafx.application.PlatformImpl.lambda$null$5(PlatformImpl.java:295)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.sun.javafx.application.PlatformImpl.lambda$runLater$6(PlatformImpl.java:294)
    at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
    at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
    at com.sun.glass.ui.win.WinApplication.lambda$null$4(WinApplication.java:186)
    ... 1 more
Exception running application main.Main

我的主文件如下（并且allatok.fxml文件位于主包中，位于main.java旁边）：

package main;

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 {

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

    @Override
    public void start(Stage primaryStage) throws Exception {
        
        Parent load = FXMLLoader.load(getClass().getResource("allatok.fxml"));
        Scene value = new Scene(load);
        primaryStage.setScene(value);

        primaryStage.setResizable(true);
        primaryStage.setTitle("Kisallat Nyilvantarto Rendszer");
        primaryStage.show();
        
    }

}

我应该在哪里放置fxml文件，以及如何重命名路径？

解决方法

在最顶部的XML标记中，您可以使用XML属性fx:controller指定完全合格的类名（FQCN）

示例：AnchorPane

<AnchorPane prefHeight="400.0" prefWidth="600.0"
    xmlns="http://javafx.com/javafx/8" xmlns:fx="http://javafx.com/fxml/1"
    fx:controller="com.zigma.Controller">

com.zigma.Controller的代码

package com.zigma;
import java.net.URL;
import java.util.ResourceBundle;
import javafx.fxml.Initializable;
public class Controller implements Initializable{
    @Override
    public void initialize(URL url,ResourceBundle resourceBundle)
    {
        System.out.println("controller init");
    }
}