Web登录状态保持之Session

我就是我 2023-10-05 14:54 50阅读 0赞

#### 下面的代码包括了登录的验证以及Session的设置 ####

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        
      
    		// 设置格式
            request.setCharacterEncoding("utf-8");
            response.setContentType("text/html;charset=utf-8");
    		
            response.setHeader("Access-Control-Allow-Origin", "*");
            response.setHeader("Access-Control-Allow-Methods", "POST");
            response.setHeader("Access-Control-Allow-Headers", "x-requested-with,content-type");
            response.setContentType("text/html;charset=utf-8");
            response.setCharacterEncoding("utf-8");
    
    
            String username = request.getParameter("username");
            String password = request.getParameter("password");
    
            UserVO user = new UserVO();
            UserDao dao = new UserDao();
    
            user.setUserName(username);
            user.setPassword(password.hashCode());
            		
    
    		// 使用request对象的getSession()获取session，如果session不存在则创建一个
            HttpSession session = request.getSession();
    		
    		// 获取session的Id
            String sessionId = session.getId();
    		// 判断session是不是新创建的
            if (session.isNew()) {
        
                response.getWriter().print("session创建成功，session的id是：" + sessionId);
            } else {
        
                System.out.println(session.getAttribute("java")); // 值myJavaData
                response.getWriter().print(
                        "服务器已经存在该session了，session的id是：" + sessionId);
    
                try {
        
                    if (dao.checkUser(user)) {
        
    
                        UserVO user_info = dao.query_info(username);
    					// 将数据存储到session中
                        session.setAttribute("username",username);
                        session.setAttribute("email",user_info.getEmail());
                        session.setAttribute("sex",user_info.getSex());
                        request.getRequestDispatcher("/personal.jsp").forward(request, response);
    
                    } else
                        request.getRequestDispatcher("/login.jsp").forward(request, response);
    
                } catch (Exception e) {
        
                    e.printStackTrace();
                    System.out.println("loginServlet,验证出错");
                }
    
            }
        }

#### 只要在jsp页面中用EL表达式就可以获取到session对象中的信息了 ####

<div class="mess" >
                    <p>用户名：${
        sessionScope.username}   </p>
                    <p>邮箱：${
        sessionScope.email}    </p>
                    <p>性别：${
        sessionScope.sex}</p>
    
                </div>