spring - Vaadin Spring Projekt 期望无参数构造函数，仅在 tomcat 而不是本地

Question

我正在尝试在 Ubuntu 18.04 服务器上的 Tomcat 应用程序服务器上使用 Spring Boot 运行 Vaadin 项目。

我下载了 Vaadin Flow Spring Starter Projekt:https://vaadin.com/start/latest/project-base-spring

但是当我将它部署到tomcat 上并尝试打开它时，出现了这个错误:

There was an exception while trying to navigate to '' with the exception message 'Unable to create an instance of 'de.web.michail.spring.MainView'. Make sure the class has a public no-arg constructor.'
java.lang.IllegalArgumentException: Unable to create an instance of 'de.web.michail.spring.MainView'. Make sure the class has a public no-arg constructor.
    at com.vaadin.flow.internal.ReflectTools.createProxyInstance(ReflectTools.java:515)
    at com.vaadin.flow.internal.ReflectTools.createInstance(ReflectTools.java:447)
    at com.vaadin.flow.di.DefaultInstantiator.getOrCreate(DefaultInstantiator.java:65)
    at com.vaadin.flow.di.Instantiator.createRouteTarget(Instantiator.java:158)
    at com.vaadin.flow.router.internal.AbstractNavigationStateRenderer.lambda$getRouteTarget$1(AbstractNavigationStateRenderer.java:116)
    at java.base/java.util.Optional.orElseGet(Optional.java:358)
    at com.vaadin.flow.router.internal.AbstractNavigationStateRenderer.getRouteTarget(AbstractNavigationStateRenderer.java:115)
    at com.vaadin.flow.router.internal.AbstractNavigationStateRenderer.handle(AbstractNavigationStateRenderer.java:167)
    at com.vaadin.flow.router.Router.handleNavigation(Router.java:221)
    at com.vaadin.flow.router.Router.navigate(Router.java:192)
    at com.vaadin.flow.router.Router.initializeUI(Router.java:95)
    at com.vaadin.flow.server.BootstrapHandler.createAndInitUI(BootstrapHandler.java:1117)
    at com.vaadin.flow.server.BootstrapHandler.synchronizedHandleRequest(BootstrapHandler.java:396)
    at com.vaadin.flow.server.SynchronizedRequestHandler.handleRequest(SynchronizedRequestHandler.java:40)
    at com.vaadin.flow.server.VaadinService.handleRequest(VaadinService.java:1533)
    at com.vaadin.flow.server.VaadinServlet.service(VaadinServlet.java:227)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:199)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:490)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
    at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:668)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343)
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:408)
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:834)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1417)
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
    at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1135)
    at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.base/java.lang.Thread.run(Thread.java:844)

我不明白为什么这个基础示例项目没有运行。你认为tomcat是问题所在吗？也许像 WildFly 这样的其他应用程序服务器可以正常运行？

Answer 1

让应用程序扩展 SpringBootServletInitializer 解决问题。

public class Application extends SpringBootServletInitializer {
// ...
}