<form action="board.html" th:action method="post">
 <div >
 <label for="title"></label>
 <input type="text" id="title" name="title" class="form-control">
 </div>

 <div class="h-75">
<div contenteditable="true" role="textbox" aria-multiline="true" class="form-control my-3" style="height: 300px; border: #1a1e21 3px";>
 </div>
 <input type="hidden" id="hiddenContent" th:name="${form.content}" th:value="${form.content}" />
 </div>

 <hr class="my-4">

 <div class="row">
 <div class="col">
 <button class="w-100 btn btn-primary btn-lg" type="submit">글 등록</button>
 </div>
 <div class="col">
 <button class="w-100 btn btn-secondary btn-lg"
 onclick="location.href='boards.html'"
 th:onclick="|location.href='@{/boards}'|"
 type="button">취소</button>
 </div>
 </div>

</form>

이고 


@PostMapping("/add")
public String writeBoard(@SessionAttribute(name = SessionConst.LOGIN_MEMBER, required = false) Member loginMember,
 @ModelAttribute Board board, RedirectAttributes redirectAttributes
) {
Board notSaveBoard = new Board();


 notSaveBoard.setBoardId(board.getBoardId());

 notSaveBoard.setTitle(board.getTitle());
 notSaveBoard.setContent(board.getContent());

 notSaveBoard.setMember(loginMember);
 Board board1 = boardService.save(notSaveBoard);
 redirectAttributes.addAttribute("boardId", board1.getBoardId());
 redirectAttributes.addAttribute("status", true);
 return "redirect:/boards/{boardId}";
}

인데 나는 저 div contenteditable 의 내용을 컨트롤러 단에서 처리하고 싶은데 어떻게 해야 하는 거에요? 

챗 지피티한테도 물어보고 별 수를 다 썼는데 지금 4시간 동안 해결방법을 찾지 못하고 있어요 씨발