1.无效的源发行版

无效的源发行版

File->Project Structure
选择 Modules ->Dependencies

SDK

选择 Modules -> Sources

language level

将Language level 8后,程序成功运行.

2.connot resolve symbol HttpServletRequest
File->Project Structure
选择 Modules ->Dependencies
选择+->library

添加Tomcat8.5.31