html如何显示会话作用域用户,html如何获取四大作用域的值？

用户提问

jsp可以有EL和JSTL获取作用域中的，那html页面？

推荐答案

给你一个小例子看看就明白了。获取用户输入参数，然后进行数据库查询，查询成功则登录成功

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public class HandleLogin extends HttpServlet{ private String backNews = ""; //登录状态返回信息 public void init(ServletConfig config) throws ServletException{ super.init(config); } public void doPost(HttpServletRequest request,HttpServletResponse response) throws ServletException,IOException{ request.setCharacterEncoding("utf-8"); response.setCharacterEncoding("utf-8"); Login loginBean = null; //JavaBean HttpSession session = request.getSession(true); try { loginBean = (Login) session.getAttribute("login"); if(loginBean == null){ loginBean = new Login(); session.setAttribute("login", loginBean); } } catch (Exception e) { loginBean = new Login(); session.setAttribute("login", loginBean); } String id = request.getParameter("id").trim(); String password = request.getParameter("password").trim(); boolean loginOk = loginBean.isLoginSuccess(); if(loginOk&&(id.equals(loginBean.getId())&&(password.equals(loginBean.getPassword())) )){ backNews = "尊敬的会员："+id+",您已经登录，无需重复登录！"; loginBean.setBackNews(backNews); } else{ boolean chkLength = id.length()>0 && password.length()>0; //判断用户名和密码是否为空 if(chkLength){ //连接数据库进行查询验证登录是否正确 Connection connection = DbConn.getConnection(); try { PreparedStatement pStatement = connection.prepareStatement("select id from member where id=? and password =?"); pStatement.setString(1, id); pStatement.setString(2, password); ResultSet resultSet = pStatement.executeQuery(); if(resultSet.next()){ backNews = "登录成功"; loginBean.setId(id); loginBean.setPassword(password); loginBean.setLoginSuccess(true); loginBean.setBackNews(backNews); } else{ backNews = "您输入的用户名不存在，或密码不匹配"; loginBean.setId(id); loginBean.setLoginSuccess(false); loginBean.setBackNews(backNews); } connection.close(); } catch (SQLException e) { backNews = "您输入的用户名不存在，或密码不匹配"; loginBean.setId(id); loginBean.setLoginSuccess(false); loginBean.setBackNews(backNews); } } else{ backNews = "用户名和密码不能为空"; loginBean.setId(id); loginBean.setLoginSuccess(false); loginBean.setBackNews(backNews); } } RequestDispatcher dispatcher = request.getRequestDispatcher("showLoginMess.jsp"); dispatcher.forward(request, response); } public void doGet(HttpServletRequest request,HttpServletResponse response) throws ServletException,IOException{ doPost(request, response); }}

代码挺粗糙的，大概意思就这样的，将就着看吧