最初，applayout的目的是占据整个空间，因此它实际上并不适用于这个用例。然而，我能够调整它的行为来适应这些设置的页脚栏。

public class MainLayout extends VerticalLayout implements RouterLayout {
    private AppLayout appLayout = new AppLayout();
    private FlexLayout childWrapper = new FlexLayout();

    public MainLayout() {
        ... setup appLayout ...
        childWrapper.setSizeFull();
        appLayout.setContent(childWrapper);

        HorizontalLayout statusBar = new HorizontalLayout();
        statusBar.setHeight("50px");
        statusBar.setWidth("100%");
        statusBar.add(new Span("Status Bar"));
        statusBar.getElement().getStyle().set("background",
                "var(--lumo-tint-30pct)");
        appLayout.getElement().getStyle().set("width", "100%");
        appLayout.getElement().getStyle().set("height", "500px");
        add(appLayout, statusBar);
        this.expand(appLayout);
    }

    @Override
    public void showRouterLayoutContent(HasElement content) {
        childWrapper.getElement().appendChild(content.getElement());
    }

}

如果你想让状态栏位于顶部，只需切换 add(appLayout, statusBar); 到 add(statusBar, appLayout);