HTML的MP4后缀链接怎么得到

使用javafx的Media，MediaPlayer，MediaView。代码如下：
import java.io.File;import javafx.application.Application;import javafx.beans.binding.Bindings;import javafx.beans.property.ReadOnlyProperty;import javafx.beans.value.ObservableValue;import javafx.event.ActionEvent;import javafx.geometry.Pos;import javafx.scene.Scene;import javafx.scene.control.Button;import javafx.scene.control.Menu;import javafx.scene.control.MenuBar;import javafx.scene.control.MenuItem;import javafx.scene.control.Slider;import javafx.scene.image.Image;import javafx.scene.image.ImageView;import javafx.scene.layout.BorderPane;import javafx.scene.layout.HBox;import javafx.scene.layout.Pane;import javafx.scene.layout.VBox;import javafx.scene.media.Media;import javafx.scene.media.MediaPlayer;import javafx.scene.media.MediaPlayer.Status;import javafx.scene.media.MediaView;import javafx.stage.FileChooser;import javafx.stage.FileChooser.ExtensionFilter;import javafx.stage.Stage;import javafx.util.Duration;public class App extends Application { private MediaView mediaView; private Slider processSlider; private static final Object AUTO = new Object(), MANUAL = new Object(); public static void main(String[] args) { launch(args); } @Override public void start(Stage primaryStage) throws Exception { primaryStage.setTitle("javafx视频播放器"); BorderPane root = new BorderPane(); // 菜单栏 initMenu(root); // 视频播放控件 mediaView = initMediaView(root); // 视频功能控件 initMediaControllView(root); primaryStage.setScene(new Scene(root, 600, 400)); primaryStage.setOnCloseRequest(event -> System.exit(0)); primaryStage.show(); } private MenuBar initMenu(final BorderPane parent) { Menu menu = new Menu("菜单"); MenuItem item = new MenuItem("打开"); item.setOnAction(event -> { FileChooser chooser = new FileChooser(); chooser.setTitle("选择视频文件"); chooser.getExtensionFilters().add(new ExtensionFilter("视频文件", "*.mp4", "*.flv")); File file = chooser.showOpenDialog(parent.getScene().getWindow()); if (file != null) { MediaPlayer player = mediaView.getMediaPlayer(); // 关闭当前的player if (player != null) { player.stop(); player.dispose(); } processSlider.setValue(0); // 创建一个新的player并自动播放 player = new MediaPlayer(new Media(file.toURI().toString())); player.currentTimeProperty().addListener(this::mediaProcessChanged); player.setAutoPlay(true); mediaView.setMediaPlayer(player); } }); menu.getItems().add(item); item = new MenuItem("退出"); item.setOnAction(event -> parent.getScene().getWindow().hide()); menu.getItems().add(item); MenuBar menuBar = new MenuBar(menu); parent.setTop(menuBar); return menuBar; } private MediaView initMediaView(final BorderPane parent) { MediaView view = new MediaView(); Pane pane = new Pane(view); parent.setCenter(pane); // 视频宽高可随着窗口变化而自动缩放 view.fitWidthProperty().bind(Bindings.selectDouble(view.parentProperty(), "width")); view.fitHeightProperty().bind(Bindings.selectDouble(view.parentProperty(), "height")); view.setPreserveRatio(true); return view; } private void initMediaControllView(final BorderPane parent) { VBox bottom = new VBox(10); bottom.setAlignment(Pos.CENTER); parent.setBottom(bottom); Slider slider = new Slider(0, 100, 0); slider.valueProperty().addListener(this::processSliderChanged);// slider.setOnMouseClicked(this::processSliderClicked); bottom.getChildren().add(slider); processSlider = slider; HBox hbox = new HBox(10); bottom.getChildren().add(hbox); hbox.setAlignment(Pos.CENTER); Button btn = new Button(null, new ImageView(loadImage("pause.png"))); btn.setOnAction(this::pauseOrPlay); hbox.getChildren().add(btn); btn = new Button(null, new ImageView(loadImage("stop.png"))); btn.setOnAction(this::stopPlay); hbox.getChildren().add(btn); } private static Image loadImage(String resPath) { return new Image(Thread.currentThread().getContextClassLoader().getResourceAsStream(resPath)); } private void pauseOrPlay(ActionEvent event) { MediaPlayer player = mediaView.getMediaPlayer(); if (player == null) { return; } Status status = player.getStatus(); if (status == Status.READY || status == Status.PAUSED) { player.play(); ((Button) event.getTarget()).setGraphic(new ImageView(loadImage("pause.png"))); } else if (status == Status.PLAYING) { player.pause(); ((Button) event.getTarget()).setGraphic(new ImageView(loadImage("play.png"))); } } private void stopPlay(ActionEvent event) { MediaPlayer player = mediaView.getMediaPlayer(); if (player == null) { return; } player.stop(); } // private void processSliderClicked(MouseEvent event) {// Slider slider = (Slider) event.getSource();// if (mediaView.getMediaPlayer() != null) {// Duration d = mediaView.getMediaPlayer().getTotalDuration().multiply(slider.getValue() / slider.getMax());// mediaView.getMediaPlayer().seek(d);// }// } private void processSliderChanged(ObservableValue observable, Number oldValue, Number newValue) { Slider slider = (Slider) ((ReadOnlyProperty) observable).getBean(); if (slider.getUserData() == AUTO) { // 进度条是自动改变的，因此不用设置播放器 slider.setUserData(null); return; } if (mediaView.getMediaPlayer() != null) { slider.setUserData(MANUAL); Duration d = mediaView.getMediaPlayer().getTotalDuration().multiply(newValue.doubleValue() / slider.getMax()) mediaView.getMediaPlayer().seek(d); } } private void mediaProcessChanged(ObservableValue observable, Duration oldValue, Duration newValue) { if (processSlider.getUserData() == MANUAL) { // 手动点击进度条 processSlider.setUserData(null); return; } MediaPlayer player = (MediaPlayer) ((ReadOnlyProperty) observable).getBean(); processSlider.setUserData(AUTO); processSlider.setValue(newValue.toMillis() / player.getTotalDuration().toMillis() * 100); } }