서버 측 에러 Resolved [org.springframework.http.converter.HttpMessageNotWritableException: Could not write JSON: Class `com.deom.model.FileData` not subtype of `java.util.Map`; nested exception is com.fasterxml.jackson.databind.JsonMappingException: Class `com.deom .model.FileData` not subtype of `java.util.Map` (through reference chain: java.util.HashMap["fileList"]->java.util.ArrayList[0])] 클라이언트 측..