Thymeleaf本页面通过controller跳转到本页面的坑

当你尝试用spring boot+thymeleaf，来实现本页面跳转到本页面功能时，我们以index通过controller跳转到index为例，你会发现，return"index"，会报如下错，太坑了解决办法，我用的是重定向"redirect:/index"

 [THYMELEAF][http-nio-8080-exec-10] Exception processing template "index": An error happened during template parsing (template: "class path resource [templates/index.html]")

org.thymeleaf.exceptions.TemplateInputException: An error happened during template parsing (template: "class path resource [templates/index.html]")
	at org.thymeleaf.templateparser.markup.AbstractMarkupTemplateParser.parse(AbstractMarkupTemplateParser.java:241) ~[thymeleaf-3.0.11.RELEASE.jar:3.0.11.RELEASE]
	at org.thymeleaf.templateparser.markup.AbstractMarkupTemplateParser.parseStandalone(AbstractMarkupTemplateParser.java:100) ~[thymeleaf-3.0.11.RELEASE.jar:3.0.11.RELEASE]
	at org.thymeleaf.engine.TemplateManager.parseAndProcess(TemplateManager.java:666) ~[thymeleaf-3.0.11.RELEASE.jar:3.0.11.RELEASE]
	```