JShell 是用于实现示例表达式的交互式工具。我们可以使用JavaFX 应用程序以编程方式实现JShell,然后需要在下面列出的Java程序中导入一些软件包
import jdk.jshell.JShell; import jdk.jshell.SnippetEvent; import jdk.jshell.VarSnippet;
在下面的示例中,实现了一个示例Java FX应用程序。我们将在文本字段中输入不同的值,然后按“ eval ”按钮。它将在列表中显示具有相应数据类型的值。
import javafx.application.Application; import javafx.scene.Scene; import javafx.scene.control.*; import javafx.scene.layout.*; import javafx.stage.Stage; import java.util.List; import jdk.jshell.JShell; import jdk.jshell.SnippetEvent; import jdk.jshell.VarSnippet; public class JShellFXTest extends Application { @Override public void start(Stage primaryStage) throws Exception { JShell shell = JShell.builder().build(); TextField textField = new TextField(); Button evalButton = new Button("eval"); ListView<String> listView = new ListView<>(); evalButton.setOnAction(e -> { List<SnippetEvent> events = shell.eval(textField.getText()); events.stream().map(event -> convert(event)).filter(s -> s != null).forEach(s -> listView.getItems().add(s)); }); BorderPane pane = new BorderPane(); pane.setTop(new HBox(textField, evalButton)); pane.setCenter(listView); Scene scene = new Scene(pane); primaryStage.setScene(scene); primaryStage.show(); } public static String convert(SnippetEvent e) { if(e.snippet() instanceof VarSnippet) { return ((VarSnippet) e.snippet()).typeName() + " " + ((VarSnippet) e.snippet()).name() + " " + e.value(); } return null; } public static void main(String[] args) { launch(); } }