JavaFX MediaPlayer抛出java.lang.reflect.InvocationTargetException

Question

I've been trying to experiment with the JavaFX MediaPlayer class, and found the following example code in a different thread:

import java.net.URI;
import java.net.URISyntaxException;

import javafx.application.Application;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.media.Media;
import javafx.scene.media.MediaPlayer;
import javafx.scene.media.MediaView;
import javafx.stage.Stage;

public class test extends Application {

    @Override
    public void start(Stage primaryStage)
    {
        //Add a scene
        Group root = new Group();
        Scene scene = new Scene(root, 500, 200);
        URI file = null;
        try {
            file = new URI("/home/thomas/voodoo.mp3");
        } catch (URISyntaxException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
            System.out.println("POOR URI SYNTAX");
        }
        Media pick = new Media(file.toString());
        MediaPlayer player = new MediaPlayer(pick);
        player.play();

        //Add a mediaView, to display the media. Its necessary !
        //This mediaView is added to a Pane
        MediaView mediaView = new MediaView(player);
        ((Group)scene.getRoot()).getChildren().add(mediaView);

        //show the stage
        primaryStage.setTitle("Media Player");
        primaryStage.setScene(scene);
        primaryStage.show();
    }
    public static void main(String[] args) {
         launch(args);
    }
}

I adjusted the file path to point to a real audio file (/home/thomas/voodoo.mp3) and tried running it, but the console output is the following:

Exception in Application start method
java.lang.reflect.InvocationTargetException
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    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(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at sun.launcher.LauncherHelper$FXHelper.main(LauncherHelper.java:767)
Caused by: java.lang.RuntimeException: Exception in Application start method
    at com.sun.javafx.application.LauncherImpl.launchApplication1(LauncherImpl.java:917)
    at com.sun.javafx.application.LauncherImpl.lambda$launchApplication$1(LauncherImpl.java:182)
    at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.IllegalArgumentException: uri.getScheme() == null! uri == '/home/thomas/voodoo.mp3'
    at com.sun.media.jfxmedia.locator.Locator.<init>(Locator.java:211)
    at javafx.scene.media.Media.<init>(Media.java:393)
    at test.start(test.java:28)
    at com.sun.javafx.application.LauncherImpl.lambda$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.gtk.GtkApplication._runLoop(Native Method)
    at com.sun.glass.ui.gtk.GtkApplication.lambda$null$5(GtkApplication.java:139)
    ... 1 more
Exception running application test

Is there something wrong with my setup, or with my code?

Thanks for the help!

EDIT:

Changed to Media pick = new Media(new File("/home/thomas/voodoo.mp3").toURI().toString()); as per Nash's suggestion, but it still doesn't work. The console output is a little different now, though.

Exception in Application start method
java.lang.reflect.InvocationTargetException
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    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(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at sun.launcher.LauncherHelper$FXHelper.main(LauncherHelper.java:767)
Caused by: java.lang.RuntimeException: Exception in Application start method
    at com.sun.javafx.application.LauncherImpl.launchApplication1(LauncherImpl.java:917)
    at com.sun.javafx.application.LauncherImpl.lambda$launchApplication$1(LauncherImpl.java:182)
    at java.lang.Thread.run(Thread.java:745)
Caused by: MediaException: UNKNOWN : com.sun.media.jfxmedia.MediaException: Could not create player! : com.sun.media.jfxmedia.MediaException: Could not create player!
    at javafx.scene.media.MediaException.exceptionToMediaException(MediaException.java:146)
    at javafx.scene.media.MediaPlayer.init(MediaPlayer.java:511)
    at javafx.scene.media.MediaPlayer.<init>(MediaPlayer.java:414)
    at test.start(test.java:20)
    at com.sun.javafx.application.LauncherImpl.lambda$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.gtk.GtkApplication._runLoop(Native Method)
    at com.sun.glass.ui.gtk.GtkApplication.lambda$null$5(GtkApplication.java:139)
    ... 1 more
Caused by: com.sun.media.jfxmedia.MediaException: Could not create player!
    at com.sun.media.jfxmediaimpl.NativeMediaManager.getPlayer(NativeMediaManager.java:274)
    at com.sun.media.jfxmedia.MediaManager.getPlayer(MediaManager.java:118)
    at javafx.scene.media.MediaPlayer.init(MediaPlayer.java:467)
    ... 11 more
Exception running application test

Answer 1

The problem is your url /home/thomas/voodoo.mp3 that is not valid, indeed the scheme is missing as described into your error message ( uri.getScheme() == null! uri == '/home/thomas/voodoo.mp3' ), it should start with file:// as it is a file in your local file system such that it should be file:///home/thomas/voodoo.mp3 .

But since it is too error prone to build the URI as you currently do because you must ensure that it is properly URL encoded (spaces should be for example replaced with %20 ) and you need to provide a valid scheme, you had better to use new File(path).toURI().toString() as proposed by Nash .

Answer 2

尝试

Media pick = new Media(new File("/home/thomas/voodoo.mp3").toURI().toString());