로그인 처리

header.jsp

<!-- 로그인을 하지 않은 경우 true -->
			<sec:authorize access="isAnonymous()">
			<a class="nav-link dropdown-toggle text-nowrap px-3"
				data-toggle="dropdown" href="#" role="button" aria-haspopup="true"
				aria-expanded="false"> <img
					class="user-avatar rounded-circle mr-2"
					src="/resources/shards/images/avatars/0.jpg" alt="User Avatar">
					<span class="d-none d-md-inline-block">Sierra Brooks</span>
			</a>
			</sec:authorize>
			<!-- 로그인 한 사용자의 경우 -->
			<sec:authorize access="isAuthenticated()">
				<sec:authentication property="principal.username" />님 &nbsp;
				<form method="post" action="/logout">
					<button type="submit" class="mb-2 btn btn-sm btn-info mr-1">로그아웃</button>
					<sec:csrfInput />
				</form>
			</sec:authorize>