使用Playing audio using JavaFX MediaPlayer in a normal Java application?接受的答案中提供的代码示例当我将绝对路径作为String传递给File构造函数时，我能够从计算机上的目录中播放mp3。
我的问题是我试图从我导入到eclipse的目录中访问mp3文件。我想这样做，以便我可以将我的项目导出为.jar并让其他人能够使用它。当我传递相对路径String（/ ProjectName / Mp3Directory）并运行它时，我得到了
Cannot find video source directory: /ProjectName/Mp3Directory
我还尝试从相对路径创建一个URL，然后将其转换为URI并将其传递给File构造函数，但我无法使其工作。
如何获取以下代码以查找包含mp3（Mp3Directory）的导入目录并成功运行？
package application;
import java.io.*;
import java.net.URL;
import java.util.*;
import javafx.application.Platform;
import javafx.beans.value.*;
import javafx.embed.swing.JFXPanel;
import javafx.event.*;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.*;
import javafx.scene.layout.*;
import javafx.scene.media.*;
import javafx.util.Duration;
import javax.swing.*;
/** Example of playing all mp3 audio files in a given directory
* using a JavaFX MediaView launched from Swing
*/
public class JavaFXVideoPlayerLaunchedFromSwing {
private static void initAndShowGUI() {
// This method is invoked on Swing thread
JFrame frame = new JFrame("FX");
final JFXPanel fxPanel = new JFXPanel();
frame.add(fxPanel);
frame.setBounds(200, 100, 800, 250);
frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
frame.setVisible(true);
Platform.runLater(new Runnable() {
@Override public void run() {
initFX(fxPanel);
}
});
}
private static void initFX(JFXPanel fxPanel) {
// This method is invoked on JavaFX thread
Scene scene = new SceneGenerator().createScene();
fxPanel.setScene(scene);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
@Override public void run() {
initAndShowGUI();
}
});
}
}
class SceneGenerator {
final Label currentlyPlaying = new Label();
final ProgressBar progress = new ProgressBar();
private ChangeListener<Duration> progressChangeListener;
public Scene createScene() {
final StackPane layout = new StackPane();
// determine the source directory for the playlist
final File dir = new File("/ProjectName/mp3Directory");
if (!dir.exists() || !dir.isDirectory()) {
System.out.println("Cannot find video source directory: " + dir);
Platform.exit();
return null;
}
// create some media players.
final List<MediaPlayer> players = new ArrayList<MediaPlayer>();
for (String file : dir.list(new FilenameFilter() {
@Override public boolean accept(File dir, String name) {
return name.endsWith(".mp3");
}
})) players.add(createPlayer("file:///" + (dir + "\\" + file).replace("\\", "/").replaceAll(" ", "%20")));
if (players.isEmpty()) {
System.out.println("No audio found in " + dir);
Platform.exit();
return null;
}
// create a view to show the mediaplayers.
final MediaView mediaView = new MediaView(players.get(0));
final Button skip = new Button("Skip");
final Button play = new Button("Pause");
// play each audio file in turn.
for (int i = 0; i < players.size(); i++) {
final MediaPlayer player = players.get(i);
final MediaPlayer nextPlayer = players.get((i + 1) % players.size());
player.setOnEndOfMedia(new Runnable() {
@Override public void run() {
player.currentTimeProperty().removeListener(progressChangeListener);
mediaView.setMediaPlayer(nextPlayer);
nextPlayer.play();
}
});
}
// allow the user to skip a track.
skip.setOnAction(new EventHandler<ActionEvent>() {
@Override public void handle(ActionEvent actionEvent) {
final MediaPlayer curPlayer = mediaView.getMediaPlayer();
MediaPlayer nextPlayer = players.get((players.indexOf(curPlayer) + 1) % players.size());
mediaView.setMediaPlayer(nextPlayer);
curPlayer.currentTimeProperty().removeListener(progressChangeListener);
curPlayer.stop();
nextPlayer.play();
}
});
// allow the user to play or pause a track.
play.setOnAction(new EventHandler<ActionEvent>() {
@Override public void handle(ActionEvent actionEvent) {
if ("Pause".equals(play.getText())) {
mediaView.getMediaPlayer().pause();
play.setText("Play");
} else {
mediaView.getMediaPlayer().play();
play.setText("Pause");
}
}
});
// display the name of the currently playing track.
mediaView.mediaPlayerProperty().addListener(new ChangeListener<MediaPlayer>() {
@Override public void changed(ObservableValue<? extends MediaPlayer> observableValue, MediaPlayer oldPlayer, MediaPlayer newPlayer) {
setCurrentlyPlaying(newPlayer);
}
});
// start playing the first track.
mediaView.setMediaPlayer(players.get(0));
mediaView.getMediaPlayer().play();
setCurrentlyPlaying(mediaView.getMediaPlayer());
// silly invisible button used as a template to get the actual preferred size of the Pause button.
Button invisiblePause = new Button("Pause");
invisiblePause.setVisible(false);
play.prefHeightProperty().bind(invisiblePause.heightProperty());
play.prefWidthProperty().bind(invisiblePause.widthProperty());
// layout the scene.
layout.setStyle("-fx-background-color: cornsilk; -fx-font-size: 20; -fx-padding: 20; -fx-alignment: center;");
layout.getChildren().addAll(
invisiblePause,
VBoxBuilder.create().spacing(10).alignment(Pos.CENTER).children(
currentlyPlaying,
mediaView,
HBoxBuilder.create().spacing(10).alignment(Pos.CENTER).children(skip, play, progress).build()
).build()
);
progress.setMaxWidth(Double.MAX_VALUE);
HBox.setHgrow(progress, Priority.ALWAYS);
return new Scene(layout, 800, 600);
}
/** sets the currently playing label to the label of the new media player and updates the progress monitor. */
private void setCurrentlyPlaying(final MediaPlayer newPlayer) {
progress.setProgress(0);
progressChangeListener = new ChangeListener<Duration>() {
@Override public void changed(ObservableValue<? extends Duration> observableValue, Duration oldValue, Duration newValue) {
progress.setProgress(1.0 * newPlayer.getCurrentTime().toMillis() / newPlayer.getTotalDuration().toMillis());
}
};
newPlayer.currentTimeProperty().addListener(progressChangeListener);
String source = newPlayer.getMedia().getSource();
source = source.substring(0, source.length() - ".mp4".length());
source = source.substring(source.lastIndexOf("/") + 1).replaceAll("%20", " ");
currentlyPlaying.setText("Now Playing: " + source);
}
/** @return a MediaPlayer for the given source which will report any errors it encounters */
private MediaPlayer createPlayer(String aMediaSrc) {
System.out.println("Creating player for: " + aMediaSrc);
final MediaPlayer player = new MediaPlayer(new Media(aMediaSrc));
player.setOnError(new Runnable() {
@Override public void run() {
System.out.println("Media error occurred: " + player.getError());
}
});
return player;
}
}
答案 0 :(得分：1)
也许尝试允许用户在createScene方法中选择包含其中mp3的文件夹：
final JFileChooser fc = new JFileChooser();
fc.setFileSelectionMode(JFileChooser.DIRECTORIES_ONLY);
// final File dir = new File("/ProjectName/mp3Directory");
File dir = null;
int selection = fc.showDialog(null, "Open");
if(selection == JFileChooser.APPROVE_OPTION) {
dir = fc.getSelectedFile();
} else {
System.out.print("Please select a directory to continue");
System.exit(0);
}
答案 1 :(得分：1)
相对路径不应以斜杠开头。 “/ ProjectName”等同于当前驱动器根目录中名为ProjectName的文件夹。所以你可以试试“ProjectName / mp3Directory”......虽然对于可以在Eclipse和可运行的JAR中运行的东西，你应该得到运行应用程序的文件夹并从那里创建一个相对路径（参见{的答案） {3}}了解更多信息）：
URL url = getClass().getResource("").toURI().toURL();
String applicationDir = url.getPath();
if(url.getProtocol().equals("jar")) {
appDir = new File(((JarURLConnection)url.openConnection()).getJarFileURL().getFile()).().getFile()).getParent();
}
String mp3Dir = appDir + "ProjectName" + System.getProperty("file.separator") + "mp3Directory";
即使它不是你的问题的直接答案，我认为对于一个通用的应用程序，你不想强迫用户将他们的MP3文件放在特定的文件夹中，axiopisty建议使用文件选择器（与使用设置文件或首选项API保存选项一起使用）将是最佳选择。