从JavaFx运行Perl脚本

Question

I'm trying to run a Perl script from a JavaFx stage when a button is pressed.

I'm able to use Runtime.getRuntime().exec() to run the script in the public static void main(String[] args) method of the main class, but when doing this it doesn't run until the Application.launch(args) is completed. I want it to run while the stage is still active instead of having to close it.

I tried adding it to the ButtonHandlerClass as part of the public void handle(ActionEvent e) method with no luck.

Answer 1

Using the following perl script (windows perl...) where I can extend the sleep call to make it take longer the UI stays responsive while perl is doing it's thing, then the text area is updated with the string returned from perl.

ETA: Probably should have put the readers in a try-with-resources and closed them up...

my $x = '';
for (my $i=0; $i <= 1000000; $i++) {
    if ($i % 100000 == 0) {
        sleep(1);
        $x .= '> ' . $i . "\n";
    }
}
print $x;

And JavaFX

public class PTApp extends Application {

    private TextArea ta;
    private Label lblMsg;


    @Override
    public void start(Stage primaryStage) {

        VBox vb = new VBox(4);
        vb.setPadding(new Insets(4));
        Button btn = new Button();
        btn.setText("Run Script");
        btn.setOnAction((ActionEvent event) -> {
            runPerlScript();
        });

        lblMsg = new Label("Ready...");

        ta = new TextArea();
        VBox.setVgrow(ta, Priority.ALWAYS);

        vb.getChildren().addAll(btn, lblMsg, ta);

        Scene scene = new Scene(vb, 600, 650);

        primaryStage.setTitle("Perl Test");
        primaryStage.setScene(scene);
        primaryStage.show();
    }


    private void runPerlScript() {
        ta.setText("About to begin...");

        PerlTask pt = new PerlTask();
        lblMsg.textProperty().bind(pt.messageProperty());
        pt.stateProperty().addListener((obs, os, ns) -> {
            //System.out.println("Worker state changed: " + ns.toString());
            if (Worker.State.SUCCEEDED.equals(ns)) {
                Platform.runLater(() -> {
                    ta.setText(pt.getValue());
                });
            } else if (Worker.State.FAILED.equals(ns)) {
                ta.setText(pt.getException().getMessage());
            }
        });

        Thread th = new Thread(pt);
        th.start();

    }


    public static class PerlTask extends Task<String> {

        @Override
        protected String call() throws Exception {

            updateMessage("About to call Perl...");

            Process pp = Runtime.getRuntime().exec("C:\\Perl64\\bin\\perl.exe D:\\PerlTest\\perl\\test.pl");

            updateMessage("Perl called, building readers...");

            BufferedReader br = new BufferedReader(new InputStreamReader(pp.getInputStream()));
            BufferedReader brE = new BufferedReader(new InputStreamReader(pp.getErrorStream()));

            StringBuilder sb = new StringBuilder("--------Perl Output\n");
            String l;
            while ((l = br.readLine()) != null) {
                sb.append(l).append("\n");
            }

            updateMessage("Input stream read...");
            sb.append("\n");
            sb.append("--------Perl Errors\n");
            while ((l = brE.readLine()) != null) {
                sb.append(l).append("\n");
            }

            updateMessage("Error stream read...");

            return sb.toString();

        }

    }

}