[ 참고 자료 ]
MVC: https://shallow-learning.tistory.com/entry/%EC%8A%A4%ED%94%84%EB%A7%81%EB%B6%80%ED%8A%B8-4-Spring-MVC-Controller-%EB%A7%8C%EB%93%A4%EA%B8%B0
ThymeLeaf: https://catsbi.oopy.io/32a9458e-f452-4733-b87c-caba75f98e2d
Logger: https://codechacha.com/ko/java-logging-api/
Servlet: https://velog.io/@falling_star3/Tomcat-%EC%84%9C%EB%B8%94%EB%A6%BFServlet%EC%9D%B4%EB%9E%80