解决： 在application.yml配置文件 中加上classic_compatible配置
# freemarker
freemarker:
suffix: .ftl
content-type: text/html
charset: UTF-8
template-loader-path: classpath:/views/
settings:
classic_compatible: true
SpringBoot整合FreeMarker 报错 FTL stack trace ("~" means nesting-related): - Failed at: ${ctx}
原文：https://www.cnblogs.com/withlamb/p/14985632.html