java - 使用 Vaadin 和 Spring (MySQL DB) 运行应用程序时出现问题

Question

我正在尝试按照我在此处找到的说明将 Vaadin 项目连接到 MySQL 数据库:https://dzone.com/articles/how-to-connect-a-mysql-database-to-a-vaadin-applic

我在文章中下载了现成的项目(也可以在这里:https://github.com/Liskokuningas/databasemysqlexample)

然后，我在 MySQL Workbench 中创建了虚拟数据模式，并尝试通过 Windows 10 命令行运行应用程序，如下所示:mvn clean install -U/*这里一切正常，构建成功*/然后 mvn spring-boot:run

然后我得到一个错误:

Followed by:
java.lang.RuntimeException: Unable to initialize com.vaadin.flow.spring.VaadinServletContextInitializer$VaadinAppShellContextListener
        at com.vaadin.flow.spring.VaadinServletContextInitializer$FailFastServletContextListener.contextInitialized(VaadinServletContextInitializer.java:192) ~[vaadin-spring-16.0.1.jar:na]
        at com.vaadin.flow.spring.VaadinServletContextInitializer$CompositeServletContextListener.lambda$contextInitialized$0(VaadinServletContextInitializer.java:209) ~[vaadin-spring-16.0.1.jar:na]
        at java.base/java.util.ArrayList.forEach(ArrayList.java:1511) ~[na:na]
        at com.vaadin.flow.spring.VaadinServletContextInitializer$CompositeServletContextListener.contextInitialized(VaadinServletContextInitializer.java:209) ~[vaadin-spring-16.0.1.jar:na]
        at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4680) ~[tomcat-embed-core-9.0.22.jar:9.0.22]
        at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5143) ~[tomcat-embed-core-9.0.22.jar:9.0.22]
        at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183) ~[tomcat-embed-core-9.0.22.jar:9.0.22]
        at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1384) ~[tomcat-embed-core-9.0.22.jar:9.0.22]
        at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1374) ~[tomcat-embed-core-9.0.22.jar:9.0.22]
        at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264) ~[na:na]
        at org.apache.tomcat.util.threads.InlineExecutorService.execute(InlineExecutorService.java:75) ~[tomcat-embed-core-9.0.22.jar:9.0.22]
        at java.base/java.util.concurrent.AbstractExecutorService.submit(AbstractExecutorService.java:140) ~[na:na]
        at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:909) ~[tomcat-embed-core-9.0.22.jar:9.0.22]
        at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:841) ~[tomcat-embed-core-9.0.22.jar:9.0.22]
        at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183) ~[tomcat-embed-core-9.0.22.jar:9.0.22]
        at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1384) ~[tomcat-embed-core-9.0.22.jar:9.0.22]
        at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1374) ~[tomcat-embed-core-9.0.22.jar:9.0.22]
        at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264) ~[na:na]
        at org.apache.tomcat.util.threads.InlineExecutorService.execute(InlineExecutorService.java:75) ~[tomcat-embed-core-9.0.22.jar:9.0.22]
        at java.base/java.util.concurrent.AbstractExecutorService.submit(AbstractExecutorService.java:140) ~[na:na]
        at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:909) ~[tomcat-embed-core-9.0.22.jar:9.0.22]
        at org.apache.catalina.core.StandardEngine.startInternal(StandardEngine.java:262) ~[tomcat-embed-core-9.0.22.jar:9.0.22]
        at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183) ~[tomcat-embed-core-9.0.22.jar:9.0.22]
        at org.apache.catalina.core.StandardService.startInternal(StandardService.java:421) ~[tomcat-embed-core-9.0.22.jar:9.0.22]
        at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183) ~[tomcat-embed-core-9.0.22.jar:9.0.22]
        at org.apache.catalina.core.StandardServer.startInternal(StandardServer.java:932) ~[tomcat-embed-core-9.0.22.jar:9.0.22]
        at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183) ~[tomcat-embed-core-9.0.22.jar:9.0.22]
        at org.apache.catalina.startup.Tomcat.start(Tomcat.java:456) ~[tomcat-embed-core-9.0.22.jar:9.0.22]
        at org.springframework.boot.web.embedded.tomcat.TomcatWebServer.initialize(TomcatWebServer.java:105) ~[spring-boot-2.1.7.RELEASE.jar:2.1.7.RELEASE]
        at org.springframework.boot.web.embedded.tomcat.TomcatWebServer.<init>(TomcatWebServer.java:86) ~[spring-boot-2.1.7.RELEASE.jar:2.1.7.RELEASE]
        at org.springframework.boot.web.embedded.tomcat.TomcatServletWebServerFactory.getTomcatWebServer(TomcatServletWebServerFactory.java:416) ~[spring-boot-2.1.7.RELEASE.jar:2.1.7.RELEASE]
        at org.springframework.boot.web.embedded.tomcat.TomcatServletWebServerFactory.getWebServer(TomcatServletWebServerFactory.java:180) ~[spring-boot-2.1.7.RELEASE.jar:2.1.7.RELEASE]
        at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.createWebServer(ServletWebServerApplicationContext.java:180) ~[spring-boot-2.1.7.RELEASE.jar:2.1.7.RELEASE]
        at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.onRefresh(ServletWebServerApplicationContext.java:153) ~[spring-boot-2.1.7.RELEASE.jar:2.1.7.RELEASE]
        at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:543) ~[spring-context-5.1.9.RELEASE.jar:5.1.9.RELEASE]
        at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:141) ~[spring-boot-2.1.7.RELEASE.jar:2.1.7.RELEASE]
        at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:743) ~[spring-boot-2.1.7.RELEASE.jar:2.1.7.RELEASE]
        at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:390) ~[spring-boot-2.1.7.RELEASE.jar:2.1.7.RELEASE]
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:312) ~[spring-boot-2.1.7.RELEASE.jar:2.1.7.RELEASE]
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:1214) ~[spring-boot-2.1.7.RELEASE.jar:2.1.7.RELEASE]
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:1203) ~[spring-boot-2.1.7.RELEASE.jar:2.1.7.RELEASE]
        at com.example.mysql.application.spring.Application.main(Application.java:14) ~[classes/:na]
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:64) ~[na:na]
        at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
        at java.base/java.lang.reflect.Method.invoke(Method.java:564) ~[na:na]
        at org.springframework.boot.devtools.restart.RestartLauncher.run(RestartLauncher.java:49) ~[spring-boot-devtools-2.1.7.RELEASE.jar:2.1.7.RELEASE]
Caused by: com.vaadin.flow.server.InvalidApplicationConfigurationException:

Found app shell configuration annotations in non `AppShellConfigurator` classes.
Please create a custom class implementing `AppShellConfigurator` and move the following annotations to it:
    - @PWA from com.example.mysql.application.spring.MainView

        at com.vaadin.flow.server.startup.VaadinAppShellInitializer.init(VaadinAppShellInitializer.java:157) ~[flow-server-6.0.6.jar:6.0.6]
        at com.vaadin.flow.server.startup.VaadinAppShellInitializer.init(VaadinAppShellInitializer.java:94) ~[flow-server-6.0.6.jar:6.0.6]
        at com.vaadin.flow.spring.VaadinServletContextInitializer$VaadinAppShellContextListener.failFastContextInitialized(VaadinServletContextInitializer.java:550) ~[vaadin-spring-16.0.1.jar:na]
        at com.vaadin.flow.spring.VaadinServletContextInitializer$FailFastServletContextListener.contextInitialized(VaadinServletContextInitializer.java:188) ~[vaadin-spring-16.0.1.jar:na]
        ... 46 common frames omitted

2021-07-16 19:22:03.821 ERROR 12584 --- [  restartedMain] o.apache.catalina.core.StandardContext   : One or more listeners failed to start. Full details will be found in the appropriate container log file
2021-07-16 19:22:03.823 ERROR 12584 --- [  restartedMain] o.apache.catalina.core.StandardContext   : Context [] startup failed due to previous errors
2021-07-16 19:22:03.922  INFO 12584 --- [  restartedMain] o.apache.catalina.core.StandardService   : Stopping service [Tomcat]
2021-07-16 19:22:03.928  WARN 12584 --- [  restartedMain] ConfigServletWebServerApplicationContext : Exception encountered during context initialization - cancelling refresh attempt: org.springframework.context.ApplicationContextException: Unable to start web server; nested exception is org.springframework.boot.web.server.WebServerException: Unable to start embedded Tomcat
2021-07-16 19:22:03.944  INFO 12584 --- [  restartedMain] ConditionEvaluationReportLoggingListener :

Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2021-07-16 19:22:03.948 ERROR 12584 --- [  restartedMain] o.s.boot.SpringApplication               : Application run failed

org.springframework.context.ApplicationContextException: Unable to start web server; nested exception is org.springframework.boot.web.server.WebServerException: Unable to start embedded Tomcat
        at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.onRefresh(ServletWebServerApplicationContext.java:156) ~[spring-boot-2.1.7.RELEASE.jar:2.1.7.RELEASE]
        at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:543) ~[spring-context-5.1.9.RELEASE.jar:5.1.9.RELEASE]
        at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:141) ~[spring-boot-2.1.7.RELEASE.jar:2.1.7.RELEASE]
        at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:743) ~[spring-boot-2.1.7.RELEASE.jar:2.1.7.RELEASE]
        at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:390) ~[spring-boot-2.1.7.RELEASE.jar:2.1.7.RELEASE]
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:312) ~[spring-boot-2.1.7.RELEASE.jar:2.1.7.RELEASE]
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:1214) ~[spring-boot-2.1.7.RELEASE.jar:2.1.7.RELEASE]
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:1203) ~[spring-boot-2.1.7.RELEASE.jar:2.1.7.RELEASE]
        at com.example.mysql.application.spring.Application.main(Application.java:14) ~[classes/:na]
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:64) ~[na:na]
        at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
        at java.base/java.lang.reflect.Method.invoke(Method.java:564) ~[na:na]
        at org.springframework.boot.devtools.restart.RestartLauncher.run(RestartLauncher.java:49) ~[spring-boot-devtools-2.1.7.RELEASE.jar:2.1.7.RELEASE]
Caused by: org.springframework.boot.web.server.WebServerException: Unable to start embedded Tomcat
        at org.springframework.boot.web.embedded.tomcat.TomcatWebServer.initialize(TomcatWebServer.java:124) ~[spring-boot-2.1.7.RELEASE.jar:2.1.7.RELEASE]
        at org.springframework.boot.web.embedded.tomcat.TomcatWebServer.<init>(TomcatWebServer.java:86) ~[spring-boot-2.1.7.RELEASE.jar:2.1.7.RELEASE]
        at org.springframework.boot.web.embedded.tomcat.TomcatServletWebServerFactory.getTomcatWebServer(TomcatServletWebServerFactory.java:416) ~[spring-boot-2.1.7.RELEASE.jar:2.1.7.RELEASE]
        at org.springframework.boot.web.embedded.tomcat.TomcatServletWebServerFactory.getWebServer(TomcatServletWebServerFactory.java:180) ~[spring-boot-2.1.7.RELEASE.jar:2.1.7.RELEASE]
        at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.createWebServer(ServletWebServerApplicationContext.java:180) ~[spring-boot-2.1.7.RELEASE.jar:2.1.7.RELEASE]
        at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.onRefresh(ServletWebServerApplicationContext.java:153) ~[spring-boot-2.1.7.RELEASE.jar:2.1.7.RELEASE]
        ... 13 common frames omitted
Caused by: java.lang.IllegalStateException: StandardEngine[Tomcat].StandardHost[localhost].TomcatEmbeddedContext[] failed to start
        at org.springframework.boot.web.embedded.tomcat.TomcatWebServer.rethrowDeferredStartupExceptions(TomcatWebServer.java:169) ~[spring-boot-2.1.7.RELEASE.jar:2.1.7.RELEASE]
        at org.springframework.boot.web.embedded.tomcat.TomcatWebServer.initialize(TomcatWebServer.java:108) ~[spring-boot-2.1.7.RELEASE.jar:2.1.7.RELEASE]
        ... 18 common frames omitted

虽然构建似乎是成功的，但我无法在浏览器出现 404 错误:请求的资源 [/] 不可用。

对此有什么想法吗？谁能告诉我如何将 Vaadin 连接到 MySQL 数据库？

提前致谢!

Answer 1

在堆栈跟踪中，您可以看到以下建议

Found app shell configuration annotations in non `AppShellConfigurator` classes.
Please create a custom class implementing `AppShellConfigurator` and move the following annotations to it:
    - @PWA from com.example.mysql.application.spring.MainView

因此，您必须创建一个 AppShellConfigurator 实现并将 @PWA 注释从 MainView 移至该新类。

这是文档的链接:https://vaadin.com/docs/v20/flow/advanced/modifying-the-bootstrap-page/#customizing-the-application-shell-during-runtime