SpringBoot项目打包jar后运行报错Error resolving templ ate [XXX], template might not exist

SpringBoot项目在IDEA开发期间运行一切正常，但是打成jar包后运行出现页面访问不了，报如下错误：

2020/07/26-20:42:41 [http-nio-8081-exec-3] ERROR org.thymeleaf.TemplateEngine- [THYMELEAF][http-nio-8081-exec-3] Exception processing template “/i18n/before”: Error resolving templ
ate [/i18n/before], template might not exist or might not be accessible by any of the configured Template Resolvers
org.thymeleaf.exceptions.TemplateInputException: Error resolving template [/i18n/before], template might not exist or might not be accessible by any of the configured Template Reso
lvers
at org.thymeleaf.engine.TemplateManager.resolveTemplate(TemplateManager.java:869)
at org.thymeleaf.engine.TemplateManager.parseAndProcess(TemplateManager.java:607)
。。。。。。

解决方案如下：
将"/i18n/first"前面的"/“删掉

效果如下：
删了”/“后：http://localhost:8081/i18n/first

没删”/"的：http://localhost:8081/i18n/admin