[Spring] @ManyToOne 어노테이션 3 로그인, 로그아웃

1. View 확인

    @Data
    public static class LoginDTO{
        private String username;
        private String password;

    }

2. 레파지토리

@RequiredArgsConstructor
@Repository
public class UserRepository {

    private final EntityManager em;

    public User findByUsernameAndPassword(UserRequest.LoginDTO requestDTO) {
        String q = """
                select u from User u where u.username = :username and u.password =:password
                """;
        Query query = em.createQuery(q, User.class);
        query.setParameter("username",requestDTO.getUsername());
        query.setParameter("password",requestDTO.getPassword());

        return (User) query.getSingleResult();

    }
  }

3. 컨트롤러

   //로그인
    @PostMapping("/login")
    public String login(UserRequest.LoginDTO requestDTO){

       User sessionUser = userRepository.findByUsernameAndPassword(requestDTO);
       session.setAttribute("sessionUser",sessionUser);
       return "redirect:/";
    }
    
    //로그아웃
    @GetMapping("/logout")
    public String logout() {
        session.invalidate();
        return "redirect:/";
    }

4. View 확인

            <ul class="navbar-nav">
                {{#sessionUser}}
                    <li class="nav-item">
                        <a class="nav-link" href="/board/save-form">글쓰기</a>
                    </li>
                    <li class="nav-item">
                        <a class="nav-link" href="/user/update-form">회원정보보기</a>
                    </li>
                    <li class="nav-item">
                        <a class="nav-link" href="/logout">로그아웃</a>
                    </li>
                {{/sessionUser}}
                {{^sessionUser}}
                    <li class="nav-item">
                        <a class="nav-link" href="/join-form">회원가입</a>
                    </li>
                    <li class="nav-item">
                        <a class="nav-link" href="/login-form">로그인</a>
                    </li>
                {{/sessionUser}}