Java 瓦丁导航误差

我在瓦丁的导航有问题。我把一切都想象成这样：

并尝试在互联网上搜索答案，例如：

但我仍然有一个错误：

java.lang.IllegalArgumentException: Trying to navigate to an unknown state '' and an error view provider not present
at com.vaadin.navigator.Navigator.navigateTo(Navigator.java:557) ~[vaadin-server-8.1.0.jar:8.1.0]
at com.vaadin.ui.UI.doInit(UI.java:750) ~[vaadin-server-8.1.0.jar:8.1.0]
at com.vaadin.server.communication.UIInitHandler.getBrowserDetailsUI(UIInitHandler.java:216) [vaadin-server-8.1.0.jar:8.1.0]
at com.vaadin.server.communication.UIInitHandler.synchronizedHandleRequest(UIInitHandler.java:74) [vaadin-server-8.1.0.jar:8.1.0]
at com.vaadin.server.SynchronizedRequestHandler.handleRequest(SynchronizedRequestHandler.java:41) [vaadin-server-8.1.0.jar:8.1.0]
at com.vaadin.server.VaadinService.handleRequest(VaadinService.java:1568) [vaadin-server-8.1.0.jar:8.1.0]
at com.vaadin.server.VaadinServlet.service(VaadinServlet.java:381) [vaadin-server-8.1.0.jar:8.1.0]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:742) [tomcat-embed-core-8.5.16.jar:8.5.16]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) [tomcat-embed-core-8.5.16.jar:8.5.16]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-8.5.16.jar:8.5.16]
at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:728) [tomcat-embed-core-8.5.16.jar:8.5.16]
at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:467) [tomcat-embed-core-8.5.16.jar:8.5.16]
at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:351) [tomcat-embed-core-8.5.16.jar:8.5.16]
at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:311) [tomcat-embed-core-8.5.16.jar:8.5.16]
at org.springframework.web.servlet.mvc.ServletForwardingController.handleRequestInternal(ServletForwardingController.java:133) [spring-webmvc-4.3.10.RELEASE.jar:4.3.10.RELEASE]
at org.springframework.web.servlet.mvc.AbstractController.handleRequest(AbstractController.java:174) [spring-webmvc-4.3.10.RELEASE.jar:4.3.10.RELEASE]
at org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter.handle(SimpleControllerHandlerAdapter.java:50) [spring-webmvc-4.3.10.RELEASE.jar:4.3.10.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:967) [spring-webmvc-4.3.10.RELEASE.jar:4.3.10.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:901) [spring-webmvc-4.3.10.RELEASE.jar:4.3.10.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970) [spring-webmvc-4.3.10.RELEASE.jar:4.3.10.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:872) [spring-webmvc-4.3.10.RELEASE.jar:4.3.10.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:661) [tomcat-embed-core-8.5.16.jar:8.5.16]
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846) [spring-webmvc-4.3.10.RELEASE.jar:4.3.10.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:742) [tomcat-embed-core-8.5.16.jar:8.5.16]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) [tomcat-embed-core-8.5.16.jar:8.5.16]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-8.5.16.jar:8.5.16]
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) [tomcat-embed-websocket-8.5.16.jar:8.5.16]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-8.5.16.jar:8.5.16]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-8.5.16.jar:8.5.16]
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99) [spring-web-4.3.10.RELEASE.jar:4.3.10.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-4.3.10.RELEASE.jar:4.3.10.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-8.5.16.jar:8.5.16]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-8.5.16.jar:8.5.16]
at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:105) [spring-web-4.3.10.RELEASE.jar:4.3.10.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-4.3.10.RELEASE.jar:4.3.10.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-8.5.16.jar:8.5.16]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-8.5.16.jar:8.5.16]
at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:81) [spring-web-4.3.10.RELEASE.jar:4.3.10.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-4.3.10.RELEASE.jar:4.3.10.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-8.5.16.jar:8.5.16]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-8.5.16.jar:8.5.16]
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:197) [spring-web-4.3.10.RELEASE.jar:4.3.10.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-4.3.10.RELEASE.jar:4.3.10.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-8.5.16.jar:8.5.16]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-8.5.16.jar:8.5.16]
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198) [tomcat-embed-core-8.5.16.jar:8.5.16]
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) [tomcat-embed-core-8.5.16.jar:8.5.16]
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:478) [tomcat-embed-core-8.5.16.jar:8.5.16]
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140) [tomcat-embed-core-8.5.16.jar:8.5.16]
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:80) [tomcat-embed-core-8.5.16.jar:8.5.16]
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87) [tomcat-embed-core-8.5.16.jar:8.5.16]
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342) [tomcat-embed-core-8.5.16.jar:8.5.16]
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:799) [tomcat-embed-core-8.5.16.jar:8.5.16]
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) [tomcat-embed-core-8.5.16.jar:8.5.16]
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868) [tomcat-embed-core-8.5.16.jar:8.5.16]
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1455) [tomcat-embed-core-8.5.16.jar:8.5.16]
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-8.5.16.jar:8.5.16]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [na:1.8.0_111]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [na:1.8.0_111]
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-8.5.16.jar:8.5.16]
at java.lang.Thread.run(Thread.java:745) [na:1.8.0_111]

我的班级：

@SpringUI(path = "test")
@SpringViewDisplay
@Theme("valo")
public class TestUI extends UI implements ViewDisplay {

    private Panel springViewDisplay;

    @Override
    protected void init(VaadinRequest request) {
        final VerticalLayout root = new VerticalLayout();
        root.setSizeFull();
        setContent(root);

        final CssLayout navigationBar = new CssLayout();
        navigationBar.addStyleName(ValoTheme.LAYOUT_COMPONENT_GROUP);
        navigationBar.addComponent(createNavigationButton("Login View", LoginView.VIEW_NAME));
        navigationBar.addComponent(createNavigationButton("Menu View", MenuView.VIEW_NAME));
        root.addComponent(navigationBar);

        springViewDisplay = new Panel();
        springViewDisplay.setSizeFull();
        root.addComponent(springViewDisplay);
        root.setExpandRatio(springViewDisplay, 1.0f);
    }

    private Button createNavigationButton(String caption, final String viewName) {
        Button button = new Button(caption);
        button.addStyleName(ValoTheme.BUTTON_SMALL);
        button.addClickListener(event -> getUI().getNavigator().navigateTo(viewName));
        return button;
    }

    @Override
    public void showView(View view) {
        springViewDisplay.setContent((Component) view);
    }
}

@UIScope
@SpringView(name = LoginView.VIEW_NAME)
public class LoginView extends VerticalLayout implements View {

    public static final String VIEW_NAME = "login";

    @PostConstruct
    public void init() {
        addComponent(new Label("Created View"));
    }

    @Override
    public void enter(ViewChangeListener.ViewChangeEvent event) {

    }
}

@UIScope
@SpringView(name = MenuView.VIEW_NAME)
public class MenuView extends VerticalLayout implements View {

    public static final String VIEW_NAME = "menu";

    @PostConstruct
    public void init() {
        setMargin(true);
        setSpacing(true);
        addComponent(new Label("Menu View"));
    }

    @Override
    public void enter(ViewChangeListener.ViewChangeEvent event) {

    }

}

可能是我还是做错了，或者我不完全理解它是如何工作的

PS

---

加载ui路径时会显示此错误。按钮工作正常。

我知道当您直接在浏览器中编写时会出现问题：

localhost:8080/test

，对吗？这个导航正常吗<代码>按钮.addClickListener（事件->getUI（）.getNavigator（）.navigateTo（视图名））是的，我通过添加空的起始视图解决了这个问题，现在一切正常：

getNavigator（）.addView（“，LoginView.class”）

我知道当您直接在浏览器中编写时会出现问题：

localhost:8080/test

，对吗？这个导航正常吗<代码>按钮.addClickListener（事件->getUI（）.getNavigator（）.navigateTo（视图名））是的，我通过添加空的起始视图解决了这个问题，现在一切正常：

getNavigator（）.addView（“，LoginView.class”）