如何使用PlayFramework更改引导侧栏类的活动状态？

<div class="sidebar">
  <ul>
    <li class="@if(active == "home") active @endif"><a href="/">Home</a></li>
    <li class="@if(active == "about") active @endif"><a href="/about">About</a></li>
    <li class="@if(active == "contact") active @endif"><a href="/contact">Contact</a></li>
  </ul>
</div>

public class HomeController extends Controller {
  public Result index() {
    return ok(views.html.index.render("home"));
  }
}

public class AboutController extends Controller {
  public Result about() {
    return ok(views.html.about.render("about"));
  }
}

public class ContactController extends Controller {
  public Result contact() {
    return ok(views.html.contact.render("contact"));
  }
}

@import views.html.sidebar

@main("Home") {
  @sidebar("home")
  <h1>Welcome to the Home page!</h1>
}