org.xml.sax.SAXParseException: 元素类型 "input" 必须由匹配的结束标记 "</input>" 终止。

错误记录

Spring Boot推荐使用thymeleaf作为视图，按照SpringBoot实战一书的案例写Demo。

发生错误：

org.xml.sax.SAXParseException: 元素类型 "input" 必须由匹配的结束标记 "</input>" 终止。
	at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.createSAXParseException(ErrorHandlerWrapper.java:203) ~[na:1.8.0_201]
	at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.fatalError(ErrorHandlerWrapper.java:177) ~[na:1.8.0_201]
	at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:400) [na:1.8.0_201]
	at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:327) [na:1.8.0_201]
	at com.sun.org.apache.xerces.internal.impl.XMLScanner.reportFatalError(XMLScanner.java:1472) [na:1.8.0_201]
	at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanEndElement(XMLDocumentFragmentScannerImpl.java:1749) [na:1.8.0_201]
	at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(XMLDocumentFragmentScannerImpl.java:2967) [na:1.8.0_201]
	at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:602) [na:1.8.0_201]
	at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:505) [na:1.8.0_201]
	at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:842) [na:1.8.0_201]
	at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:771) [na:1.8.0_201]
	at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:141) [na:1.8.0_201]
	at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1213) [na:1.8.0_201]
	at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(SAXParserImpl.java:643) [na:1.8.0_201]
	at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl.parse(SAXParserImpl.java:327) [na:1.8.0_201]
	at org.thymeleaf.templateparser.xmlsax.AbstractNonValidatingSAXTemplateParser.doParse(AbstractNonValidatingSAXTemplateParser.java:209) [thymeleaf-2.1.6.RELEASE.jar:2.1.6.RELEASE]
	at org.thymeleaf.templateparser.xmlsax.AbstractNonValidatingSAXTemplateParser.parseTemplateUsingPool(AbstractNonValidatingSAXTemplateParser.java:134) [thymeleaf-2.1.6.RELEASE.jar:2.1.6.RELEASE]
	at org.thymeleaf.templateparser.xmlsax.AbstractNonValidatingSAXTemplateParser.parseTemplate(AbstractNonValidatingSAXTemplateParser.java:116) [thymeleaf-2.1.6.RELEASE.jar:2.1.6.RELEASE]
	at org.thymeleaf.TemplateRepository.getTemplate(TemplateRepository.java:278) [thymeleaf-2.1.6.RELEASE.jar:2.1.6.RELEASE]
	at org.thymeleaf.TemplateEngine.process(TemplateEngine.java:1104) [thymeleaf-2.1.6.RELEASE.jar:2.1.6.RELEASE]
	at org.thymeleaf.TemplateEngine.process(TemplateEngine.java:1060) [thymeleaf-2.1.6.RELEASE.jar:2.1.6.RELEASE]
	at org.thymeleaf.TemplateEngine.process(TemplateEngine.java:1011) [thymeleaf-2.1.6.RELEASE.jar:2.1.6.RELEASE]
	at org.thymeleaf.spring4.view.ThymeleafView.renderFragment(ThymeleafView.java:335) [thymeleaf-spring4-2.1.6.RELEASE.jar:2.1.6.RELEASE]
	at org.thymeleaf.spring4.view.ThymeleafView.render(ThymeleafView.java:190) [thymeleaf-spring4-2.1.6.RELEASE.jar:2.1.6.RELEASE]
	at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1286) [spring-webmvc-4.3.13.RELEASE.jar:4.3.13.RELEASE]
	at org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:1041) [spring-webmvc-4.3.13.RELEASE.jar:4.3.13.RELEASE]
	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:984) [spring-webmvc-4.3.13.RELEASE.jar:4.3.13.RELEASE]
	at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:901) [spring-webmvc-4.3.13.RELEASE.jar:4.3.13.RELEASE]
	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970) [spring-webmvc-4.3.13.RELEASE.jar:4.3.13.RELEASE]
	at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861) [spring-webmvc-4.3.13.RELEASE.jar:4.3.13.RELEASE]
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:635) [tomcat-embed-core-8.5.23.jar:8.5.23]
	at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846) [spring-webmvc-4.3.13.RELEASE.jar:4.3.13.RELEASE]
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:742) [tomcat-embed-core-8.5.23.jar:8.5.23]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) [tomcat-embed-core-8.5.23.jar:8.5.23]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-8.5.23.jar:8.5.23]
	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) [tomcat-embed-websocket-8.5.23.jar:8.5.23]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-8.5.23.jar:8.5.23]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-8.5.23.jar:8.5.23]
	at org.apache.shiro.web.servlet.AbstractShiroFilter.executeChain(AbstractShiroFilter.java:449) [shiro-web-1.3.2.jar:1.3.2]
	at org.apache.shiro.web.servlet.AbstractShiroFilter$1.call(AbstractShiroFilter.java:365) [shiro-web-1.3.2.jar:1.3.2]
	at org.apache.shiro.subject.support.SubjectCallable.doCall(SubjectCallable.java:90) [shiro-core-1.3.2.jar:1.3.2]
	at org.apache.shiro.subject.support.SubjectCallable.call(SubjectCallable.java:83) [shiro-core-1.3.2.jar:1.3.2]
	at org.apache.shiro.subject.support.DelegatingSubject.execute(DelegatingSubject.java:383) [shiro-core-1.3.2.jar:1.3.2]
	at org.apache.shiro.web.servlet.AbstractShiroFilter.doFilterInternal(AbstractShiroFilter.java:362) [shiro-web-1.3.2.jar:1.3.2]
	at org.apache.shiro.web.servlet.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:125) [shiro-web-1.3.2.jar:1.3.2]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-8.5.23.jar:8.5.23]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-8.5.23.jar:8.5.23]
	at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99) [spring-web-4.3.13.RELEASE.jar:4.3.13.RELEASE]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-4.3.13.RELEASE.jar:4.3.13.RELEASE]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-8.5.23.jar:8.5.23]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-8.5.23.jar:8.5.23]
	at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:108) [spring-web-4.3.13.RELEASE.jar:4.3.13.RELEASE]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-4.3.13.RELEASE.jar:4.3.13.RELEASE]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-8.5.23.jar:8.5.23]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-8.5.23.jar:8.5.23]
	at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:81) [spring-web-4.3.13.RELEASE.jar:4.3.13.RELEASE]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-4.3.13.RELEASE.jar:4.3.13.RELEASE]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-8.5.23.jar:8.5.23]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-8.5.23.jar:8.5.23]
	at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:197) [spring-web-4.3.13.RELEASE.jar:4.3.13.RELEASE]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-4.3.13.RELEASE.jar:4.3.13.RELEASE]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-8.5.23.jar:8.5.23]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-8.5.23.jar:8.5.23]
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:199) [tomcat-embed-core-8.5.23.jar:8.5.23]
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) [tomcat-embed-core-8.5.23.jar:8.5.23]
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:595) [tomcat-embed-core-8.5.23.jar:8.5.23]
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140) [tomcat-embed-core-8.5.23.jar:8.5.23]
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81) [tomcat-embed-core-8.5.23.jar:8.5.23]
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87) [tomcat-embed-core-8.5.23.jar:8.5.23]
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342) [tomcat-embed-core-8.5.23.jar:8.5.23]
	at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:803) [tomcat-embed-core-8.5.23.jar:8.5.23]
	at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) [tomcat-embed-core-8.5.23.jar:8.5.23]
	at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868) [tomcat-embed-core-8.5.23.jar:8.5.23]
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1459) [tomcat-embed-core-8.5.23.jar:8.5.23]
	at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-8.5.23.jar:8.5.23]
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [na:1.8.0_201]
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [na:1.8.0_201]
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-8.5.23.jar:8.5.23]
	at java.lang.Thread.run(Thread.java:748) [na:1.8.0_201]

错误原因和解决方法

Thymeleaf 3.0以前语法限制严格，每个标签必须结束，Spring Boot 2.x不会有这种情况。

1. 如果坚持使用低版本Thymeleaf，则补全结束标签，例如：

<link></link>
或
<link />

Request method 'POST' not supported

2)升级Thymeleaf版本
有两种方法
1. 一是直接在项目`pom.xml`中显式指定Thymeleaf版本号（不推介）
在项目的`pom.xml`文件的<project>节点中添加thymeleaf.version版本属性

3.0.11.REALEASE
3.0.11.REALEASE
3.0.4.RELEASE

```
2. 使用Spring Boot 2.x（目前最新版本）替换陈旧的Spring Boot 1.x，在project结点下加入以下内容。
```

org.springframework.boot
spring-boot-starter-parent
2.1.5.RELEASE

```