Failed to convert value of type 'java.lang.String' to required type 'java.lang.Integer'; nested exception is java.lang.NumberFormatException: For input string: "{id}"
<form th:action="@{/user/{id}/checkout/cancel/{orderItemId}(id=${user.id}, orderItemId=${orderItem.id})}" th:method="POST">
<input id="id" name="id" type="hidden" />
<input id="orderItemId" name="orderItemId" type="hidden" />
<td class="btn btn-outline-dark"><button type="submit">주문취소</button></td>
</form>
id와 orderItemId에 정수값이 넘어가지 않고 문자열이 넘어간다는 뜻인 것 같다.
<form th:action="@{/user/{id}/checkout/cancel/{orderItemId}(id=${user.id}, orderItemId=${orderItem.id})}" th:method="POST">
<input id="id" name="id" type="number" />
<input id="orderItemId" name="orderItemId" type="number" />
<td class="btn btn-outline-dark"><button type="submit">주문취소</button></td>
</form>
type="number"로 바꾸니까 정수값으로 잘 넘어간다.