[WARNING] Using platform encoding (UTF-8 actually) to copy filtered resources, i.e. build is platform dependent!
[WARNING] File encoding has not been set, using platform encoding UTF-8, i.e. build is platform dependent!

이런 오류가 발생하면 maven의 pom.xml에 프로젝트의 소스코드 인코딩과 출력 인코딩을 지정하여 해결할 수 있음

<properties>
  <project.build.sourceEncoding>utf-8</project.build.sourceEncoding>
  <project.reporting.outputEncoding>utf-8</project.reporting.outputEncoding>
</properties>