JavaFX TextArea字符串读取问题

import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.TextArea;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;

public class Main extends Application {

    @Override
    public void start(Stage primaryStage) {
        TextArea textArea = new TextArea();

        Button button = new Button("获取字符串内容");
        button.setOnAction(event -> {
            String content = textArea.getText();
            System.out.println("TextArea内容：" + content);
        });

        VBox root = new VBox(textArea, button);
        Scene scene = new Scene(root, 300, 200);

        primaryStage.setScene(scene);
        primaryStage.show();
    }

    public static void main(String[] args) {
        launch(args);
    }
}