import com.vaadin.sass.SassCompiler; //导入依赖的package包/类
private void compileTheme() {
    try {
        binder.commit();
        ServletContext context = VaadinServlet.getCurrent().getServletContext();
        String fullPath = context.getRealPath("/VAADIN/themes/dashboard");
        String customScssFileName = fullPath + "/custom.scss";
        SassCompiler.writeFile(customScssFileName, module.getModel());

        ProcessBuilder processBuilder = new ProcessBuilder("java", "-cp", "../../../WEB-INF/lib/*", "com.vaadin.sass.SassCompiler", "styles.scss", "styles.css");
        processBuilder.directory(new File(fullPath));
        File error = new File(fullPath, "custom.scss.log");
        processBuilder.redirectErrorStream(true);
        processBuilder.redirectError(Redirect.PIPE);
        Process process = processBuilder.start();
        process.waitFor();

        BufferedReader reader = new BufferedReader(new InputStreamReader(process.getErrorStream()));
        StringBuilder builder = new StringBuilder();
        String line = reader.readLine();
        while (line != null) {
            builder.append(line);
            line = reader.readLine();
        }
        reader.close();
        if (!builder.toString().trim().isEmpty()) {
            throw new Exception(builder.toString());
        }

    } catch (Exception ex) {
        logger.log(Level.SEVERE, ex.getMessage(), ex);
        Notification.show("Error", ex.getMessage(), Notification.Type.ERROR_MESSAGE);
    }
}
 

import com.vaadin.sass.SassCompiler; //导入依赖的package包/类
public static void main(String args[]) throws Exception {
    SassCompiler.main(new String[]{"src/main/resources/VAADIN/themes/" + Version.THEME_MOBILE_VERSION + "/styles.scss",
            "src/main/resources/VAADIN/themes/" + Version.THEME_MOBILE_VERSION + "/styles.css"});
    Path source = FileSystems.getDefault().getPath("src/main/resources/VAADIN/themes/" + Version.THEME_MOBILE_VERSION + "/", "styles.css");
    Path dest = FileSystems.getDefault().getPath("target/classes/VAADIN/themes/" + Version.THEME_MOBILE_VERSION + "/", "styles.css");
    Files.copy(source, dest, StandardCopyOption.REPLACE_EXISTING);
}
 

import com.vaadin.sass.SassCompiler; //导入依赖的package包/类
public static void main(String args[]) throws Exception {
    SassCompiler.main(new String[]{"src/main/resources/VAADIN/themes/" + Version.THEME_VERSION + "/styles.scss",
            "src/main/resources/VAADIN/themes/" + Version.THEME_VERSION +"/styles.css"});
    Path source = FileSystems.getDefault().getPath("src/main/resources/VAADIN/themes/" + Version.THEME_VERSION + "/", "styles.css");
    Path dest = FileSystems.getDefault().getPath("target/classes/VAADIN/themes/" + Version.THEME_VERSION + "/", "styles.css");
    Files.copy(source, dest, StandardCopyOption.REPLACE_EXISTING);
}