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我正在尝试使用 IntelliJ Idea 创建 javafx 小程序。构建后，我得到三个文件：.jar、.jnlp 和 .html。如果我启动 jar 一切正常，但如果我尝试使用 jnlp 或 html 运行应用程序，则会引发异常：

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？Jar 恰好包含位于指定路径的所需 fxml。

爪哇：

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>

我究竟做错了什么？请帮忙。

4

2 回答 2

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问题出在这一行：

Parent root = FXMLLoader.load(getClass().getResource("/sample/sample.fxml"));

很明显，该load方法实际上是用null参数调用的。发生这种情况是因为getResource("/sample/sample.fxml")无法归档该资源。

运行时类路径上的资源丢失（或路径错误）。

于 2015-05-30T23:44:55.113 回答
0

这是一个安全问题。FXML 文件被认为是从客户端的文件系统加载的，但是 Java 安全管理器不容忍“user.dir, read”权限。

但是，这是签署 JavaFX 小程序的问题。签署后，加载工作正常。此处示例：http ://web.univ-pau.fr/~barbier/PauWare/My_device/dist/My_device_JavaFX.html

顺便说一句，JavaFX 应用程序（例如http://www.franckbarbier.com/PauWare/Programmable_thermostat/）在代码中具有自包含小部件（不加载 FXML 文件）没有问题。干杯！！

于 2016-01-12T14:40:24.480 回答