使用代理存储库时，尝试在Vaadin 14中运行"Hello World“时出错
使用代理存储库时，尝试在Vaadin 14中运行"Hello World“时出错
提问于 2021-04-27 06:03:58
我从"start.vaadin.com“下载了这个项目。然后我做了"mvn安装“，一切正常。
当我运行"mvn spring-boot: run“时，它在尝试编译前端时产生错误："com.vaadin.flow.server.BootstrapException: Unable to read webpack统计文件。”
我不使用Maven Central，而是使用我大学的本地存储库。我的PC不能访问互联网，只能访问我的大学的Nexus库："http://nexus.prod.uci.cu/repository/maven-all/"。这个存储库有maven和node (即npm)服务。但是，正如您所看到的，没有依赖关系问题。"mvn安装“工作正常。我关闭了防火墙。然而，我推断问题出在Vaadin在编译前端时执行的"npm install“。有可能我的PC正在尝试使用来自Internet的Node存储库，而不是我的大学的存储库，在这种情况下，它不能使用，因为它不能访问Internet。我将我的npm配置为使用我的大学的存储库，但我一直收到这个错误。
以下是等待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 morepom.xml与从Vaadin站点生成的one相同。我已经在Vaadin页面上写过了。
我用"Hello World in Vaadin“评论了一些发生在我身上的奇怪的事情。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"正如"https://vaadin.com/learn/tutorials/import-maven-project-eclipse“中所解释的那样
这对我不起作用。即使在生产模式下："mvn jetty:run -Pproduction“。浏览器启动，不会生成错误，但不会显示"Hello World“应该显示的内容。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，浏览器正在运行该应用程序。
为什么这种情况发生在jetty上而不是spring-boot上？
回答 1
Stack Overflow用户
发布于 2021-04-28 12:36:58
例外似乎是尝试连接到webpack-dev-server以从生成的统计信息中获取资产。
要排除软件包和连接的问题，您可以尝试使用mvn spring-boot:run -Pproduction运行生产构建。如果能正常工作，那么至少可以正确下载node和maven包。
如果生产模式可以工作，那么在运行开发模式时，可能会在日志Webpack failed with the exception:中显示devServer无法启动的信息，以及有关原因的一些信息。
另外，通过将记录器设置为log debug，您应该获得用于启动webpack-dev-server的命令字符串，如下所示
[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 `在本例中，您可以转到localhost:62103来尝试连接到devServer。这应该会向您显示一个仅包含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
获得调试日志的方法是将行logging.level.root = debug添加到application.properties中。由于有大量的输出，我建议通过管道连接到一个文件，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。
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/67274356
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