JSP页面访问用户验证(3)

    String userPwd = request.getParameter("userpwd").trim(); 
     
    if(userName == null || userPwd == null){ 
        response.sendRedirect("userlogin.html"); 
        return; 
    } 
     
    if(userName.equals(USERNAME) && userPwd.equals(USERPWD)) { 
        session.setMaxInactiveInterval(30*60);          // 设置session失效时间（timeout），单位为秒 
        session.setAttribute("userinfo", USERNAME);     // 用户名和密码正确，保存登录信息 
        response.sendRedirect("page111.jsp"); 
    } else { 
        response.sendRedirect("userlogin.html");        // 用户名和密码错误，跳转到登录界面 
    } 
%> 

2） Java（Serlvet）后台验证（Login.java）
[java]
public class Login extends HttpServlet { 
    private static final long serialVersionUID = 1L; 
     
    private final static String USERNAME = "admin"; 
    private final static String USERPWD = "123456"; 
     
    @Override 
    protected void doGet(HttpServletRequest request, HttpServletResponse response) { 
    } 
 
    @Override 
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 
        request.setCharacterEncoding("utf-8"); 
         
        String userName = request.getParameter("username").trim(); 
        String userPwd = request.getParameter("userpwd").trim(); 
         
        if(userName == null || userPwd == null) { 
            response.sendRedirect("userlogin.html"); 
        } 
         
        if(userName.equals(USERNAME) && userPwd.equals(USERPWD)) { 
            request.getSession().setMaxInactiveInterval(30*60);     // 设置session失效时间（timeout），单位为秒