java - 如何在方法之间传输字符串(Java)

Question

本质上，我正在尝试收集字符串数据并在另一种方法中使用它。无论我尝试过什么似乎都不起作用。请检查我的代码并告诉我该怎么做。

• 我尝试将该字符串声明为公共(public)字符串，但由于它位于方法中，所以我不能这样做。
• 我的目标是将字符串“application_1”传输到button3的setOnAction方法。

@Override
    public void start(Stage primaryStage) throws Exception {
        window = primaryStage;
        window.setTitle("myDesktop");
        window.setOnCloseRequest(e -> closeProgram());

        button = new Button("Setup MyDesktop");
        button3 = new Button("Start Test Application");

        button2 = new Button("Choose Wheel Applications");
        button2.setOnAction(e -> {
            JFileChooser jfc = new JFileChooser();
            jfc.showDialog(null, "Please select a file.");
            jfc.setVisible(true);
            File filename = jfc.getSelectedFile();
            String application_1 = filename.getName();
            if (application_1.endsWith(".exe")) {
                System.out.println("File successfully chosen!");

            } else {
                System.out.println("File is not an application!");
                System.out.println("Please choose another file!");
                System.out.println("Issue Alert Box here...");
            }
            if (application_1 == null) {
                System.out.println("No file selected!");
    }
        });

        button.setOnAction(e -> {
            AlertBox.display("Alert", "Save file?");
        });
        button3.setOnAction(e -> {
            Runtime runtime = Runtime.getRuntime();
            try {
                Process process = runtime.exec("name_of_file");
            } catch (IOException e1) {
                e1.printStackTrace();
            }
        });

我希望代码能够使用该字符串

button3.setOnAction(e -> {
// code
});

Answer 1

应该有效:

@Override
    public void start(Stage primaryStage) throws Exception {
        window = primaryStage;
        window.setTitle("myDesktop");
        window.setOnCloseRequest(e -> closeProgram());
        String application_1 = ""; 

        button = new Button("Setup MyDesktop");
        button3 = new Button("Start Test Application");

        button2 = new Button("Choose Wheel Applications");
        button2.setOnAction(e -> {
            JFileChooser jfc = new JFileChooser();
            jfc.showDialog(null, "Please select a file.");
            jfc.setVisible(true);
            File filename = jfc.getSelectedFile();
            application_1 = filename.getName();
            if (application_1.endsWith(".exe")) {
                System.out.println("File successfully chosen!");

            } else {
                System.out.println("File is not an application!");
                System.out.println("Please choose another file!");
                System.out.println("Issue Alert Box here...");
            }
            if (application_1 == null) {
                System.out.println("No file selected!");
    }
        });

        button.setOnAction(e -> {
            AlertBox.display("Alert", "Save file?");
        });
        button3.setOnAction(e -> {
            Runtime runtime = Runtime.getRuntime();
            System.out.println(application_1); //here you can use the variable

            try {

                Process process = runtime.exec("name_of_file");
            } catch (IOException e1) {
                e1.printStackTrace();
            }
        });