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
Tomcat启动出错and端口占用等问题
竹杖芒鞋轻胜马，谁怕？一蓑烟雨任平生。
料峭春风吹酒醒，微冷，山头斜照却相迎。