线程“main”中的JavaFX异常java.lang.NoClassDefFoundError：javafx / application / Application [英] JavaFX Exception in thread "main" java.lang.NoClassDefFoundError: javafx/application/Application

问题描述

我收到此错误

Exception in thread "main" java.lang.NoClassDefFoundError: javafx/application/Ap
plication
        at java.lang.ClassLoader.defineClass1(Native Method)
        at java.lang.ClassLoader.defineClass(Unknown Source)
        at java.security.SecureClassLoader.defineClass(Unknown Source)
        at java.net.URLClassLoader.defineClass(Unknown Source)
        at java.net.URLClassLoader.access$100(Unknown Source)
        at java.net.URLClassLoader$1.run(Unknown Source)
        at java.net.URLClassLoader$1.run(Unknown Source)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        at sun.launcher.LauncherHelper.checkAndLoadMain(Unknown Source)
Caused by: java.lang.ClassNotFoundException: javafx.application.Application
        at java.net.URLClassLoader$1.run(Unknown Source)
        at java.net.URLClassLoader$1.run(Unknown Source)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        ... 13 more

尝试运行我的类文件时，这是源

When trying to run my class file, this is the source

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

import java.util.concurrent.Executor;

public class TestApplication extends Application{

    @Override
    public void start(Stage stage) throws Exception {
        new TestApplication();
    }

    public TestApplication() {
        try{
            final Parent root = FXMLLoader.load(Executor.class.getResource("test.fxml"));
            final Stage stage = new Stage(){{
                setScene(new Scene(root, 300, 250));
                setTitle("Test");
                setResizable(false);
                show();
            }};
        }catch(Exception e){
            e.printStackTrace();
        }
    }
}

fxml文件包含一个简单的gui。

The fxml file contains a simple gui.

推荐答案

过去几个小时我一直在研究这个问题。即使我没有明确地看到它，但似乎你必须使用一个JavaFX打包工具，它是Ant任务或javafxpackager可执行文件。 （参见 http://docs.oracle.com/javafx/2/deployment/packaging.htm，第5.3.1节）。 NetBeans IDE使用Ant来打包代码。 （我正在使用IntelliJ）

I've worked on this very same issue for the past few hours. Even though I haven't seen it written explicitly, it appears that you MUST use one of the JavaFX packaging tools, which is either an Ant task or the javafxpackager executable. (See http://docs.oracle.com/javafx/2/deployment/packaging.htm, section 5.3.1). The NetBeans IDE uses Ant to package the code. (I'm using IntelliJ)

当您使用其中一种打包方法时，除了所有应用程序的代码和资源外，它还会在输出中添加以下内容JAR文件：

When you use one of those packaging methods, in addition to all of your application's code and resources, it also adds the following to your output JAR file:

/com/javafx/main/Main$1.class
/com/javafx/main/Main$2.class
/com/javafx/main/Main.class
/com/javafx/main/NoJavaFXFallback.class

有了这些，你可以从命令行运行应用程序：

With these in place, you can run the app from the command line:

java -jar outjar.jar

并且一切正常。如果我删除额外的com.javafx.main文件，则该应用程序不会运行。

and all works fine. If I remove the extra com.javafx.main files, the app does not run.

要仔细检查，我查看了JavaFX示例中的所有四个JAR文件（BrickBreaker，Ensemble，FXML-LoginDemo和SwingInterop）。它们都有额外文件。

To double-check this, I looked at all four JAR files in the JavaFX samples (BrickBreaker, Ensemble, FXML-LoginDemo, and SwingInterop). They all have the "extra" files, too.

对于我的小型测试应用程序，我使用此命令行构建可执行JAR文件：

For my small test app, I used this command line to build an "executable" JAR file:

javafxpackager -createjar -appclass sample.Main -outfile outjar -v -nocss2bin -srcdir C:\workspaces\garoup1\out\production\javafx1

希望这会有所帮助！

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