Whitelabel Error Page 500の原因と対処法：Spring Bootでのトラブルシューティング

Whitelabel Error Page
This application has no explicit mapping for /error, so you are seeing this as a fallback.

Fri Oct 11 06:43:42 JST 2024
There was an unexpected error (type=Internal Server Error, status=500).
An error happened during template parsing (template: "class path resource [templates/studytime/studyTimeForm.html]")
org.thymeleaf.exceptions.TemplateInputException: An error happened during template parsing (template: "class path resource [templates/studytime/studyTimeForm.html]")
	at org.thymeleaf.templateparser.markup.AbstractMarkupTemplateParser.parse(AbstractMarkupTemplateParser.java:241)
	at org.thymeleaf.templateparser.markup.AbstractMarkupTemplateParser.parseStandalone(AbstractMarkupTemplateParser.java:100)
	at org.thymeleaf.engine.TemplateManager.parseAndProcess(TemplateManager.java:666)
	at org.thymeleaf.TemplateEngine.process(TemplateEngine.java:1103)
	at org.thymeleaf.TemplateEngine.process(TemplateEngine.java:1077)
	at org.thymeleaf.spring6.view.ThymeleafView.renderFragment(ThymeleafView.java:372)
	at org.thymeleaf.spring6.view.ThymeleafView.render(ThymeleafView.java:192)
	at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1432)
	at org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:1168)
	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1106)
	at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:979)
	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1014)
	at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:903)
	at jakarta.servlet.http.HttpServlet.service(HttpServlet.java:564)
	at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:885)
	at jakarta.servlet.http.HttpServlet.service(HttpServlet.java:658)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:195)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:140)
	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:51)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:164)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:140)
	at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100)
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:164)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:140)
	at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93)
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:164)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:140)
	at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201)
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:164)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:140)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:167)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:90)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:483)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:115)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:93)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:344)
	at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:384)
	at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:63)
	at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:905)
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1741)
	at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:52)
	at org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1190)
	at org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659)
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:63)
	at java.base/java.lang.Thread.run(Thread.java:833)
Caused by: org.attoparser.ParseException: Could not parse as expression: "{startTime}" (template: "studytime/studyTimeForm" - line 18, col 47)
	at org.attoparser.MarkupParser.parseDocument(MarkupParser.java:393)
	at org.attoparser.MarkupParser.parse(MarkupParser.java:257)
	at org.thymeleaf.templateparser.markup.AbstractMarkupTemplateParser.parse(AbstractMarkupTemplateParser.java:230)
	... 48 more
Caused by: org.thymeleaf.exceptions.TemplateProcessingException: Could not parse as expression: "{startTime}" (template: "studytime/studyTimeForm" - line 18, col 47)
	at org.thymeleaf.standard.expression.StandardExpressionParser.parseExpression(StandardExpressionParser.java:131)
	at org.thymeleaf.standard.expression.StandardExpressionParser.parseExpression(StandardExpressionParser.java:62)
	at org.thymeleaf.standard.expression.StandardExpressionParser.parseExpression(StandardExpressionParser.java:44)
	at org.thymeleaf.spring6.util.FieldUtils.getBindStatus(FieldUtils.java:244)
	at org.thymeleaf.spring6.util.FieldUtils.getBindStatus(FieldUtils.java:227)
	at org.thymeleaf.spring6.processor.AbstractSpringFieldTagProcessor.doProcess(AbstractSpringFieldTagProcessor.java:174)
	at org.thymeleaf.processor.element.AbstractAttributeTagProcessor.doProcess(AbstractAttributeTagProcessor.java:74)
	at org.thymeleaf.processor.element.AbstractElementTagProcessor.process(AbstractElementTagProcessor.java:95)
	at org.thymeleaf.util.ProcessorConfigurationUtils$ElementTagProcessorWrapper.process(ProcessorConfigurationUtils.java:633)
	at org.thymeleaf.engine.ProcessorTemplateHandler.handleStandaloneElement(ProcessorTemplateHandler.java:918)
	at org.thymeleaf.engine.TemplateHandlerAdapterMarkupHandler.handleStandaloneElementEnd(TemplateHandlerAdapterMarkupHandler.java:260)
	at org.thymeleaf.templateparser.markup.InlinedOutputExpressionMarkupHandler$InlineMarkupAdapterPreProcessorHandler.handleStandaloneElementEnd(InlinedOutputExpressionMarkupHandler.java:256)
	at org.thymeleaf.standard.inline.OutputExpressionInlinePreProcessorHandler.handleStandaloneElementEnd(OutputExpressionInlinePreProcessorHandler.java:169)
	at org.thymeleaf.templateparser.markup.InlinedOutputExpressionMarkupHandler.handleStandaloneElementEnd(InlinedOutputExpressionMarkupHandler.java:104)
	at org.attoparser.HtmlElement.handleStandaloneElementEnd(HtmlElement.java:79)
	at org.attoparser.HtmlMarkupHandler.handleStandaloneElementEnd(HtmlMarkupHandler.java:241)
	at org.attoparser.MarkupEventProcessorHandler.handleStandaloneElementEnd(MarkupEventProcessorHandler.java:327)
	at org.attoparser.ParsingElementMarkupUtil.parseStandaloneElement(ParsingElementMarkupUtil.java:96)
	at org.attoparser.MarkupParser.parseBuffer(MarkupParser.java:706)
	at org.attoparser.MarkupParser.parseDocument(MarkupParser.java:301)
	... 50 more

<form th:action="@{/studytime}" th:object="${studyTimeObject}" method="post">
		<label>開始時間:</label>
		<input type="datetime-local" id="startTime" th:field="{startTime}" required />
		<button type="button" onclick="setCurrentTime('startTime')">学習開始</button>
		
		<label>終了時間</label>
		<input type="datetime-local" id="endTime" th:field="*{endTime}" required />
		<button type="button" onclick="setCurrentTime('endTime')">学習終了</button>
		
		<button type="submit">保存</button>
</form>

<input type="datetime-local" id="startTime" th:field="{startTime}" required />