第十二节：session使用

一：thymeleaf中使用session
    1.基础对象访问(#session，需要contoller/action(HttpSession session))
        <!-- 基础对象，等同于#httpSession(javax.servlet.http.HttpSession)-- >
        <span th:text="${#session.getAttribute('')}">
        <span th:text="${#session.getId()}">
    2.web环境对象(#httpSession，需要contoller/action(HttpSession session)
        javax.servlet.http.HttpSession实例)
        --><!-- web环境对象(javax.servlet.http.HttpSession实例)-- >
        <span th:text="${#httpSession.getAttribute('')}">
        <span th:text="${#httpSession.getId()}">
    3.web环境属性(session)
        <!-- web环境属性(session属性) -->
        <span th:text="${session.size()}">
        <span th:text="${session.id}">
        <!--<span th:text="${session.getId()}"></span> 错误的 -->
        <span th:text="${session.isEmpty()}">
        <span th:text="${session.keyname}">
二：sessio使用
1.Action设置：session.setAttribute("sessionBk", new LogonUser("Bk001", "BkCaff", "Bk000"));
2.Action获取：
    1)代码直接获取
        LogonUser logonUser1=(LogonUser) session.getAttribute("sessionBk");
    2)action参数利用@SessionAttribute进行获取
        public ModelAndView showList(@SessionAttribute("sessionBk") LogonUser logonUser){
            System.out.println(logonUser.getUserId());
        }
    3)class's @SessionAttributes("sessionKey")+action参数@ModelAttribute("sessionKey")获取
        @SessionAttributes("sessionBk")//类上
        public class GirlController {
            //action参数中
            public ModelAndView showList(@ModelAttribute("sessionBk") LogonUser logonUser2){
                System.out.println(logonUser2.getUserId());
            }
        }
3.thymeleaf获取：
    以web环境session属性为例
    <span th:text="${session.sessionBk.userId}">