后台代码

        @At
	@POST
	@Ok("jsp:jsp.register")
	public void register(@Param("username") String username, @Param("password") String password, HttpSession session) {
		User user = userService.addUser(username, password);
		if (user != null) {
			session.setAttribute("user", user);
		}
		System.out.println(session.getAttribute("user"));
	}

前台jstl

<c:choose>
		<c:when test="${!empty session.user}">
			<c:out value="${session.user.username}"></c:out>
		</c:when>
		<c:otherwise>
			<form action="${base}/user/register" method="post">
				<input type="text" name="username"> <input type="password"
					name="password"> <input type="submit" value="register">
			</form>
		</c:otherwise>
	</c:choose>

debug后台session有值了，但是走不到${!empty session.user}，是jstl错了吗？还有${obj}是指代的什么？？？