遇到这样的问题，就得好好检查下模版
18/03/10 10:36:21 ERROR TemplateEngine: [THYMELEAF][http-nio-8080-exec-4] Exception processing template "cleandata": Could not parse as expression: "css/bootstrap.min14ed.css" (cleandata:10)
18/03/10 10:36:21 ERROR [dispatcherServlet]: Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.thymeleaf.exceptions.TemplateProcessingException: Could not parse as expression: "css/bootstrap.min14ed.css" (cleandata:10)] with root cause
org.thymeleaf.exceptions.TemplateProcessingException: Could not parse as expression: "css/bootstrap.min14ed.css" (cleandata:10)
at org.thymeleaf.standard.expression.StandardExpressionParser.parseExpression(StandardExpressionParser.java:238)
at org.thymeleaf.standard.expression.StandardExpressionParser.parseExpression(StandardExpressionParser.java:79)
at org.thymeleaf.standard.expression.StandardExpressionParser.parseExpression(StandardExpressionParser.java:40)
at org.thymeleaf.standard.processor.attr.AbstractStandardSingleAttributeModifierAttrProcessor.getTargetAttributeValue(AbstractStandardSingleAttributeModifierAttrProcessor.java:65)
at org.thymeleaf.spring4.processor.attr.SpringHrefAttrProcessor.getTargetAttributeValue(SpringHrefAttrProcessor.java:68)
at org.thymeleaf.processor.attr.AbstractSingleAttributeModifierAttrProcessor.getModifiedAttributeValues(AbstractSingleAttributeModifierAttrProcessor.java:59)
at org.thymeleaf.processor.attr.AbstractAttributeModifierAttrProcessor.processAttribute(AbstractAttributeModifierAttrProcessor.java:62)
at org.thymeleaf.processor.attr.AbstractAttrProcessor.doProcess(AbstractAttrProcessor.java:87)
at org.thymeleaf.processor.AbstractProcessor.process(AbstractProcessor.java:212)
at org.thymeleaf.dom.Node.applyNextProcessor(Node.java:1017)
at org.thymeleaf.dom.Node.processNode(Node.java:972)
at org.thymeleaf.dom.NestableNode.computeNextChild(NestableNode.java:695)
at org.thymeleaf.dom.NestableNode.doAdditionalProcess(NestableNode.java:668)
at org.thymeleaf.dom.Node.processNode(Node.java:990)
at org.thymeleaf.dom.NestableNode.computeNextChild(NestableNode.java:695)
at org.thymeleaf.dom.NestableNode.doAdditionalProcess(NestableNode.java:668)
at org.thymeleaf.dom.Node.processNode(Node.java:990)
at org.thymeleaf.dom.NestableNode.computeNextChild(NestableNode.java:695)
at org.thymeleaf.dom.NestableNode.doAdditionalProcess(NestableNode.java:668)
at org.thymeleaf.dom.Node.processNode(Node.java:990)
at org.thymeleaf.dom.Document.process(Document.java:93)
at org.thymeleaf.TemplateEngine.process(TemplateEngine.java:1155)
at org.thymeleaf.TemplateEngine.process(TemplateEngine.java:1060)
at org.thymeleaf.TemplateEngine.process(TemplateEngine.java:1011)
at org.thymeleaf.spring4.view.ThymeleafView.renderFragment(ThymeleafView.java:335)
at org.thymeleaf.spring4.view.ThymeleafView.render(ThymeleafView.java:190)
at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1257)
at org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:1037)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:980)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:897)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970)
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:622)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:230)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165)
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165)
at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:89)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165)
at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:77)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165)
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:197)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:108)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:349)
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:784)
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:802)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1410)
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:745)
我们发现HTML里其中一个出错的地方是这么写的：
<link th:href="css/bootstrap.min14ed.css" href="../static/css/bootstrap.min14ed.css"
rel="stylesheet" />而正确的写法应该是：
<link th:href="${'css/bootstrap.min14ed.css'}" href="../static/css/bootstrap.min14ed.css"
rel="stylesheet" />请加上${''}把字符串括起来。
原因：Thymeleaf解析的是变量，而不是字符串，要显示转换成字符串，才能解决不能parse表达式的问题
附录：在webstorm如何用正则表达式快速给""里面的内容加上${}
th:src="(.*?)"
th:src="\${'$1'}"用()括起来的内容，可以在替换栏处用$1来引用，其中数字1代表匹配遇到的第一个括号里面的内容。2、3、4……以此类推