@NotEmpty
private String userId;
-->
/* @NotEmpty */
private String userId;
(https://tecoble.techcourse.co.kr/post/2020-09-20-validation-in-spring-boot/)
@NotEmpty
private String userId;
-->
/* @NotEmpty */
private String userId;
(https://tecoble.techcourse.co.kr/post/2020-09-20-validation-in-spring-boot/)