[jquery]ajax Content type 'application/x-www-form-urlencoded;charset=UTF-8' not supported

원인 : ajax 통신 시, contentType이 맞지 않아서 발생한 오류.

[해결] 스크립트 상 ajax 구문에 
contentType: 'application/json' 추가

cf.컨트롤러에서 
@RequestBody Map<String, Object> params 
를 통해 넘어온 data 확인 가능