Springboot整合html 报java.lang.IllegalArgumentException: Root element name cannot be null
解决:
<!DOCTYPE>
<html>
改为
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">