Thymeleaf的Could not parse as expression問題解決

遇到這樣的問題，就得好好檢查下模版

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)

咱們發現HTML裏其中一個出錯的地方是這麼寫的：

<link th:href="css/bootstrap.min14ed.css" href="../static/css/bootstrap.min14ed.css"
          rel="stylesheet" />

而正確的寫法應該是：

<link th:href="${'css/bootstrap.min14ed.css'}" href="../static/css/bootstrap.min14ed.css"
              rel="stylesheet" />

請加上${''}把字符串括起來。

緣由：Thymeleaf解析的是變量，而不是字符串，要顯示轉換成字符串，才能解決不能parse表達式的問題

 

 

 

附錄：在webstorm如何用正則表達式快速給""裏面的內容加上${}

th:src="(.*?)"

th:src="\${'$1'}"

用()括起來的內容，能夠在替換欄處用$1來引用，其中數字1表明匹配遇到的第一個括號裏面的內容。二、三、4……以此類推