从JavaFX的小程序加载的NullPointerException文件FXML [英] NullPointerException loading fxml file from javafx applet

问题描述

我试图创建JavaFX的小程序，使用IntelliJ IDEA的。建成后，我得到三个文件：的.jar，的.jnlp和.html。如果我启动罐子一切工作正常，但如果我尝试用JNLP运行应用程序或HTML它抛出异常：

I'm trying to create javafx applet, using IntelliJ Idea. After building I get three files: .jar, .jnlp and .html. If I launch jar all works fine, but if I try to run app using jnlp or html it throws exception:

java.lang.NullPointerException: Location is required.
    at javafx.fxml.FXMLLoader.loadImpl(Unknown Source)
    at javafx.fxml.FXMLLoader.loadImpl(Unknown Source)
    at javafx.fxml.FXMLLoader.loadImpl(Unknown Source)
    at javafx.fxml.FXMLLoader.loadImpl(Unknown Source)
    at javafx.fxml.FXMLLoader.loadImpl(Unknown Source)
    at javafx.fxml.FXMLLoader.load(Unknown Source)
    at sample.Main.start(Main.java:14)
    at com.sun.javafx.applet.FXApplet2$2.run(Unknown Source)
    at com.sun.javafx.application.PlatformImpl.lambda$null$170(Unknown Source)
    at com.sun.javafx.application.PlatformImpl$$Lambda$45/31918841.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.sun.javafx.application.PlatformImpl.lambda$runLater$171(Unknown Source)
    at com.sun.javafx.application.PlatformImpl$$Lambda$44/13936151.run(Unknown Source)
    at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(Unknown Source)
    at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
    at com.sun.glass.ui.win.WinApplication.lambda$null$145(Unknown Source)
    at com.sun.glass.ui.win.WinApplication$$Lambda$34/10055096.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)
Exception in thread "JavaFX Application Thread" java.lang.RuntimeException: java.lang.NullPointerException: Location is required.
    at com.sun.javafx.applet.FXApplet2$2.run(Unknown Source)
    at com.sun.javafx.application.PlatformImpl.lambda$null$170(Unknown Source)
    at com.sun.javafx.application.PlatformImpl$$Lambda$45/31918841.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.sun.javafx.application.PlatformImpl.lambda$runLater$171(Unknown Source)
    at com.sun.javafx.application.PlatformImpl$$Lambda$44/13936151.run(Unknown Source)
    at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(Unknown Source)
    at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
    at com.sun.glass.ui.win.WinApplication.lambda$null$145(Unknown Source)
    at com.sun.glass.ui.win.WinApplication$$Lambda$34/10055096.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.NullPointerException: Location is required.
    at javafx.fxml.FXMLLoader.loadImpl(Unknown Source)
    at javafx.fxml.FXMLLoader.loadImpl(Unknown Source)
    at javafx.fxml.FXMLLoader.loadImpl(Unknown Source)
    at javafx.fxml.FXMLLoader.loadImpl(Unknown Source)
    at javafx.fxml.FXMLLoader.loadImpl(Unknown Source)
    at javafx.fxml.FXMLLoader.load(Unknown Source)
    at sample.Main.start(Main.java:14)
    ... 11 more

为什么会这样呢？究竟罐含有所需FXML位于指定的路径。

Why is it so? Jar exactly contains needed fxml located at the specified path.

Java的：

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/sample.fxml"));
        primaryStage.setTitle("Hello World");
        primaryStage.setScene(new Scene(root, 600, 400));
        primaryStage.show();
    }

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

FXML：

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

<?import javafx.scene.control.*?>
<?import javafx.scene.layout.*?>

<AnchorPane prefHeight="400.0" prefWidth="600.0" xmlns="http://javafx.com/javafx/8" xmlns:fx="http://javafx.com/fxml/1">
   <children>
      <Button layoutX="173.0" layoutY="188.0" prefHeight="25.0" prefWidth="255.0" text="Button" />
   </children>
</AnchorPane>

我是什么做错了吗？请帮助。

What am I doing wrong? Help please.

推荐答案

这是安全性的问题。该FXML文件被认为是被从客户端的文件系统加载，但user.dir来，读取权限没有被Java安全管理的耐受性。

This is a problem of security. The FXML file is considered as to be loaded from the filesystem of the client, but the "user.dir, read" permission is not tolerated by the Java security manager.

但是，它是签约JavaFX的小程序的问题。一旦签署，装载效果很好。例如，在这里： http://web.univ-pau.fr /~barbier/PauWare/My_device/dist/My_device_JavaFX.html

However, it is a problem of signing JavaFX applets. Once signed, the loading works well. Example here: http://web.univ-pau.fr/~barbier/PauWare/My_device/dist/My_device_JavaFX.html

BTW，没有与JavaFX应用程序没有问题
（例如， http://www.franckbarbier.com/PauWare/Programmable_thermostat/ ）有在code自足的小部件（不FXML文件加载）。干杯!!

BTW, there is no problem with JavaFX applications (eg, http://www.franckbarbier.com/PauWare/Programmable_thermostat/) that have self-contained widgets in the code (no load of FXML file). Cheers!!

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