这个小视频介绍得很详细，可以看看
https://www.bilibili.com/video/BV1J4411877m?p=222
"Error running 'Tomcat 9.0.43': Address localhost:8080 is already is use"
端口占用问题，参考
https://blog.csdn.net/eagleuniversityeye/article/details/79985027