通过命令行切换到Nashorn JavaScript引擎

我正尝试在使用nashorn的Java环境中运行以下代码。 Code Doc 通过命令行切换到Nashorn JavaScript引擎

load("fx:base.js"); 
load("fx:controls.js"); 
load("fx:graphics.js"); 

var material = new PhongMaterial(); 
material.diffuseColor = Color.LIGHTGREEN; 
material.specularColor = Color.rgb(30, 30, 30); 

var meshView = Java.to([ 
    new Box(200, 200, 200), 
    new Sphere(100), 
    new Cylinder(100, 200) 
], "javafx.scene.shape.Shape3D[]"); 

for (var i = 0; i != 3; i++) { 
    meshView[i].material = material; 
    meshView[i].translateX = (i + 1) * 220; 
    meshView[i].translateY = 200; 
    meshView[i].translateZ = 20; 
    meshView[i].drawMode = DrawMode.FILL; 
    meshView[i].cullFace = CullFace.BACK; 
}; 

var pointLight = new PointLight(Color.WHITE); 
pointLight.translateX = 800; 
pointLight.translateY = -200; 
pointLight.translateZ = -1000; 

var root = new Group(meshView); 
root.children.add(pointLight); 

var scene = new Scene(root, 800, 400, true); 
scene.fill = Color.rgb(127, 127, 127); 
scene.camera = new PerspectiveCamera(false); 
$STAGE.scene = scene; 
$STAGE.show();

它使用JavaScript API来创建JavaFx场景。

如果您使用-fx开关它能正常工作，但如果执行通过Java代码犀牛脚本引擎相同的文件，它会引发以下异常

Exception in thread "main" java.lang.ExceptionInInitializerError 
    at java.lang.Class.forName0(Native Method) 
    at java.lang.Class.forName(Class.java:348) 
    at jdk.nashorn.internal.runtime.Context.findClass(Context.java:983) 
    at jdk.nashorn.internal.objects.NativeJava.simpleType(NativeJava.java:489) 
    at jdk.nashorn.internal.objects.NativeJava.type(NativeJava.java:320) 
    at jdk.nashorn.internal.objects.NativeJava.type(NativeJava.java:312) 
    at jdk.nashorn.internal.objects.NativeJava.type(NativeJava.java:308) 
    at jdk.nashorn.internal.scripts.Script$Recompilation$3$500A$\=fx\!base.LOAD_FX_CLASSES(fx:base.js:38) 
    at jdk.nashorn.internal.scripts.Script$4$\=fx\!controls.:program(fx:controls.js:30) 
    at jdk.nashorn.internal.runtime.ScriptFunctionData.invoke(ScriptFunctionData.java:636) 
    at jdk.nashorn.internal.runtime.ScriptFunction.invoke(ScriptFunction.java:229) 
    at jdk.nashorn.internal.runtime.ScriptRuntime.apply(ScriptRuntime.java:387) 
    at jdk.nashorn.internal.runtime.Context.evaluateSource(Context.java:1150) 
    at jdk.nashorn.internal.runtime.Context.load(Context.java:799) 
    at jdk.nashorn.internal.objects.Global.load(Global.java:995) 
    at jdk.nashorn.internal.scripts.Script$\^eval\_.:program(<eval>:2) 
    at jdk.nashorn.internal.runtime.ScriptFunctionData.invoke(ScriptFunctionData.java:636) 
    at jdk.nashorn.internal.runtime.ScriptFunction.invoke(ScriptFunction.java:229) 
    at jdk.nashorn.internal.runtime.ScriptRuntime.apply(ScriptRuntime.java:387) 
    at jdk.nashorn.api.scripting.NashornScriptEngine.evalImpl(NashornScriptEngine.java:437) 
    at jdk.nashorn.api.scripting.NashornScriptEngine.evalImpl(NashornScriptEngine.java:401) 
    at jdk.nashorn.api.scripting.NashornScriptEngine.evalImpl(NashornScriptEngine.java:397) 
    at jdk.nashorn.api.scripting.NashornScriptEngine.eval(NashornScriptEngine.java:147) 
    at javax.script.AbstractScriptEngine.eval(AbstractScriptEngine.java:212) 
    at com.metalop.nashorn.javafx.GettingStarted.main(GettingStarted.java:23) 
Caused by: java.lang.IllegalStateException: Toolkit not initialized 
    at com.sun.javafx.application.PlatformImpl.runLater(PlatformImpl.java:273) 
    at com.sun.javafx.application.PlatformImpl.runLater(PlatformImpl.java:268) 
    at com.sun.javafx.application.PlatformImpl.setPlatformUserAgentStylesheet(PlatformImpl.java:550) 
    at com.sun.javafx.application.PlatformImpl.setDefaultPlatformUserAgentStylesheet(PlatformImpl.java:512) 
    at javafx.scene.control.Control.<clinit>(Control.java:87) 
    ... 25 more

那么，如何做jjs命令行实用程序我通过-fx开关或在java代码中初始化javafx for nashorn？

来源

2016-08-12 Shiva

我认为关键部分是根'IllegalStateException：Toolkit未初始化'异常。这意味着你正在运行JavaFX代码而没有启动JavaFX（'javafx.application.Application'）。所以一个解决方案应该是用'javafx.application.Application'运行你的java应用程序，而不是任何'Main'类。 –

@NikosParaskevopoulos：从Application扩展类确实会加载依赖关系并解决问题。感谢您的评论...！ – Shiva

有几件事情，我做了JavaScript的工作，因为传递-fx nashorn arg没有为我工作。

正如尼科斯在评论中提到的类必须从javafx.application.‌Application延伸，然后主要功能应调用这对于犀牛初始化和JS脚本执行的代码launch()。
启动方法有start(Stage primaryStage)签名。评估时，必须将Stage对象绑定到JavaScript。

以下代码是我如何实现它的示例。

import java.io.BufferedReader; 
import java.io.InputStream; 
import java.io.InputStreamReader; 

import javax.script.ScriptEngine; 
import javax.script.ScriptEngineManager; 
import javax.script.SimpleBindings; 

import javafx.application.Application; 
import javafx.stage.Stage; 

public class GettingStarted extends Application { 

    public static void main(String args[]) { 

     launch(args); 
    } 

    @Override 
    public void start(Stage primaryStage) throws Exception { 
     ScriptEngine engine = new ScriptEngineManager().getEngineByName("nashorn"); 

     try (InputStream is = GettingStarted.class.getResourceAsStream("getting-started.js")) { 

      BufferedReader reader = new BufferedReader(new InputStreamReader(is)); 
      SimpleBindings bindings = new SimpleBindings(); 
      bindings.put("$STAGE", primaryStage); 
      engine.eval(reader, bindings); 


     } catch (Exception e) { 
      e.printStackTrace(); 
     } 

    } 

}

来源

2016-08-16 07:22:11 Shiva