내가 하고 있는 프로젝트는 header.jsp에 넣어줌.
<!-- Spring Security tag -->
<%@ taglib prefix="sec" uri="http://www.springframework.org/security/tags" %>
<!-- Spring Security Login Session 처리 -->
<sec:authorize access="isAuthenticated()">
<sec:authentication property="principal" var="principal"/>
</sec:authorize>
<c:choose>
<!-- Session에 principal 항목이 미할당 되어있다면 (로그인X) -->
<c:when test="${empty principal}">
<ul class="navbar-nav">
<li class="nav-item"><a class="nav-link" href="/auth/loginForm">로그인</a></li>
<li class="nav-item"><a class="nav-link" href="/auth/joinForm">회원가입</a></li>
</ul>
</c:when>
<c:otherwise>
<ul class="navbar-nav">
<li class="nav-item"><a class="nav-link" href="/board/form">글쓰기</a></li>
<li class="nav-item"><a class="nav-link" href="/user/form">회원정보</a></li>
<li class="nav-item"><a class="nav-link" href="/logout">로그아웃</a></li>
</ul>
</c:otherwise>
</c:choose>