使用代理存储库时尝试在 Vaadin 14 中运行“Hello World”时出错

如何解决使用代理存储库时尝试在 Vaadin 14 中运行“Hello World”时出错

我从“start.vaadin.com”下载了该项目。然后我做了“mvn install”，一切正常。

当我运行“mvn spring-boot:run”时，它在尝试编译前端时产生一个错误：“com.vaadin.flow.server.BootstrapException: Unable to read webpack stats file。”

我不使用 Maven Central，而是使用我大学的本地存储库。我的 PC 无法访问 Internet，只能访问我大学的 Nexus 存储库：“http://nexus.prod.uci.cu/repository/maven-all/”。此存储库具有 maven 和节点（即 npm）服务。但是，如您所见，不存在依赖性问题。 “mvn install”工作正常。我禁用了防火墙。但是，我推断问题在于 Vaadin 在尝试编译前端时所做的“npm install”。有可能我的 PC 正在尝试使用 Internet 上的 Node 存储库而不是我大学的存储库，在这种情况下它不能，因为它没有 Internet 访问权限。我将我的 npm 配置为使用我大学的存储库，但我不断收到此错误。

这是等待大约三分钟后的浏览器输出：

Whitelabel Error Page

This application has no explicit mapping for /error,so you are seeing this as a fallback.
Mon Apr 26 17:55:55 GMT-05:00 2021
There was an unexpected error (type=Internal Server Error,status=500).
com.vaadin.flow.server.BootstrapException: Unable to read webpack stats file.
com.vaadin.flow.server.ServiceException: com.vaadin.flow.server.BootstrapException: Unable to read webpack stats file.
    at com.vaadin.flow.server.VaadinService.handleExceptionDuringRequest(VaadinService.java:1596)
    at com.vaadin.flow.server.VaadinService.handleRequest(VaadinService.java:1559)
    at com.vaadin.flow.server.VaadinServlet.service(VaadinServlet.java:247)
    at com.vaadin.flow.spring.SpringServlet.service(SpringServlet.java:111)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:733)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:227)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
    at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:710)
    at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:457)
    at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:352)
    at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:312)
    at org.springframework.web.servlet.mvc.ServletForwardingController.handleRequestInternal(ServletForwardingController.java:141)
    at org.springframework.web.servlet.mvc.AbstractController.handleRequest(AbstractController.java:177)
    at org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter.handle(SimpleControllerHandlerAdapter.java:52)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1060)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:962)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006)
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:626)
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:733)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:227)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
    at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
    at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:542)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:143)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:357)
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:374)
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:893)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1707)
    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)
Caused by: com.vaadin.flow.server.BootstrapException: Unable to read webpack stats file.
    at com.vaadin.flow.server.BootstrapHandler$BootstrapPageBuilder.setupFrameworkLibraries(BootstrapHandler.java:894)
    at com.vaadin.flow.server.BootstrapHandler$BootstrapPageBuilder.setupDocumentHead(BootstrapHandler.java:771)
    at com.vaadin.flow.server.BootstrapHandler$BootstrapPageBuilder.getBootstrapPage(BootstrapHandler.java:540)
    at com.vaadin.flow.server.BootstrapHandler.synchronizedHandleRequest(BootstrapHandler.java:481)
    at com.vaadin.flow.server.SynchronizedRequestHandler.handleRequest(SynchronizedRequestHandler.java:40)
    at com.vaadin.flow.server.VaadinService.handleRequest(VaadinService.java:1547)
    ... 52 more
Caused by: java.net.ConnectException: Connection refused: connect
    at java.base/java.net.DualStackPlainSocketImpl.waitForConnect(Native Method)
    at java.base/java.net.DualStackPlainSocketImpl.socketConnect(DualStackPlainSocketImpl.java:85)
    at java.base/java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:400)
    at java.base/java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:243)
    at java.base/java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:225)
    at java.base/java.net.PlainSocketImpl.connect(PlainSocketImpl.java:148)
    at java.base/java.net.Socket.connect(Socket.java:591)
    at java.base/sun.net.NetworkClient.doConnect(NetworkClient.java:177)
    at java.base/sun.net.www.http.HttpClient.openServer(HttpClient.java:474)
    at java.base/sun.net.www.http.HttpClient.openServer(HttpClient.java:569)
    at java.base/sun.net.www.http.HttpClient.<init>(HttpClient.java:242)
    at java.base/sun.net.www.http.HttpClient.New(HttpClient.java:341)
    at java.base/sun.net.www.http.HttpClient.New(HttpClient.java:362)
    at java.base/sun.net.www.protocol.http.HttpURLConnection.getNewHttpClient(HttpURLConnection.java:1242)
    at java.base/sun.net.www.protocol.http.HttpURLConnection.plainConnect0(HttpURLConnection.java:1181)
    at java.base/sun.net.www.protocol.http.HttpURLConnection.plainConnect(HttpURLConnection.java:1075)
    at java.base/sun.net.www.protocol.http.HttpURLConnection.connect(HttpURLConnection.java:1009)
    at java.base/sun.net.www.protocol.http.HttpURLConnection.getInputStream0(HttpURLConnection.java:1581)
    at java.base/sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1509)
    at java.base/java.net.HttpURLConnection.getResponseCode(HttpURLConnection.java:527)
    at com.vaadin.flow.server.frontend.FrontendUtils.getStatsAssetsByChunkName(FrontendUtils.java:566)
    at com.vaadin.flow.server.BootstrapHandler$BootstrapPageBuilder.appendNpmBundle(BootstrapHandler.java:910)
    at com.vaadin.flow.server.BootstrapHandler$BootstrapPageBuilder.setupFrameworkLibraries(BootstrapHandler.java:892)
    ... 57 more

pom.xml 与从 Vaadin 站点生成的相同。我已经在 Vaadin 页面上写过。

我用“Vaadin 中的Hello World”评论了发生在我身上的一些奇怪的事情。当我从 maven 原型创建项目时，如下所示：

"mvn -B archetype:generate -DarchetypeGroupId=com.vaadin -DarchetypeArtifactId=vaadin-archetype-application -DarchetypeVersion=LATEST -DgroupId=org.test -DartifactId=webapp -Dversion=1.0-SNAPSHOT"

如“https://vaadin.com/learn/tutorials/import-maven-project-eclipse”中所述

这对我不起作用。即使在生产模式下：“mvn jetty:run -Pproduction”。浏览器启动后不会产生错误，但不会显示“Hello World”应显示的内容。它显示了一个通知“you are offline",and explaining that "my app needs internet connection to work. You do not seem to have access to the server right now. Check your internet conecction and try reloading the page to use the application”的页面。附件是我的屏幕图像，浏览器运行应用程序。

为什么在 jetty 而不是 spring-boot 会发生这种情况？

解决方法

异常似乎是尝试连接到 webpack-dev-server 以从生成的统计信息中获取资产。

要排除包和连接的问题，您可以尝试使用 mvn spring-boot:run -Pproduction 运行生产版本。如果可行，那么至少可以正确下载 node 和 maven 包。

如果生产模式有效，那么在运行开发模式时，日志中可能会有 Webpack failed with the exception: 表明 devServer 无法启动以及一些有关原因的信息。

此外，通过将记录器设置为日志调试，您应该获得用于启动 webpack-dev-server 的命令字符串，类似于

[0m2021-04-28 07:25:38.105 DEBUG 60260 --- [         task-2] dev-webpack                              : 
C:\Program Files\nodejs\node.exe \ 
    .\node_modules\webpack-dev-server\bin\webpack-dev-server.js \ 
    --config .\webpack.config.js --port 62103 \ 
    --watchDogPort=62102 -d --inline=false `

在这种情况下，您可以通过转到 localhost:62103 尝试连接到 devServer。这应该会向您显示一个只有 config 文件夹的文件夹结构，但是如果您转到 localhost:62103/stats.json，您应该会收到一个以 {"hash":"c827122594d41ad4f7df","assetsByChunkName":{"bundle":"build/vaadin-bundle-...

开头的 json 文件

获取调试日志的方法是在 application.properties 中添加行 logging.level.root = debug。由于有很多输出，我建议管道到文件，例如运行 mvn > out.txt 并从文本文件中搜索错误和信息。

希望这有助于找出问题所在。

使用代理存储库时尝试在 Vaadin 14 中运行“Hello World”时出错

如何解决使用代理存储库时尝试在 Vaadin 14 中运行“Hello World”时出错

解决方法

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