官方原文如下：
When running a Spring Boot application that uses an embedded servlet container (and is packaged as an executable archive), there are some limitations in the JSP support.
- With Tomcat it should work if you use war packaging, i.e. an executable war will work, and will also be deployable to a standard container (not limited to, but including Tomcat). An executable jar will not work because of a hard coded file pattern in Tomcat.
- With Jetty it should work if you use war packaging, i.e. an executable war will work, and will also be deployable to any standard container.
- Undertow does not support JSPs.
- Creating a custom
error.jsppage won’t override the default view for error handling, custom error pages should be used instead.
There is a JSP sample so you can see how to set things up.
https://docs.spring.io/spring-boot/docs/current/reference/htmlsingle/#boot-features-jsp-limitations