登录检查:

    1. @GetMapping("/main.html")
    2.     public String mainPage(HttpSession session, Model model){
    3.         Object loginUser = session.getAttribute("loginUser");
    4.         if(loginUser != null){
    5.             return "main";
    6.         }else{
    7.             model.addAttribute("msg": "请重新登陆");
    8.             return "login";
    9.         }
    10.     }

    太麻烦了
    拦截器接口: handlerInterceptor
    image.png

    1. public interface HandlerInterceptor {
    2.     default boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
    3.         return true;
    4.     }
    6.     default void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, @Nullable ModelAndView modelAndView) throws Exception {
    7.     }
    9.     default void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, @Nullable Exception ex) throws Exception {
    10.     }
    11. }

    弄拦截器:

    • 定义类

      1. public class LoginInterceptor implements HandlerInterceptor {
      2.   // 目标方法执行之前
      3.   @Override
      4.   public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
      5.       HttpSession session = request.getSession();
      6.       Object loginUser = session.getAttribute("loginUser");
      7.       if(loginUser != null){
      8.           return true;
      9.       }else{
      10.           session.setAttribute("msg", "请先登陆");
      11.           response.sendRedirect("/");
      12.           return false;
      13.       }
      15.   }
      17.   // 目标方法执行完之后
      18.   @Override
      19.   public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
      20.       HandlerInterceptor.super.postHandle(request, response, handler, modelAndView);
      21.   }
      23.   // 页面渲染只后
      24.   @Override
      25.   public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
      26.       HandlerInterceptor.super.afterCompletion(request, response, handler, ex);
      27.   }
      28. }

    • 配置 -> 实现WebMvcConfigurer的addInterceptor方法

    新建配置类
    image.png

    1. @Configuration
    2. public class AdminWebConfig implements WebMvcConfigurer {
    3.     @Override
    4.     public void addInterceptors(InterceptorRegistry registry) {
    5.         registry.addInterceptor(new LoginInterceptor())
    6.                 .addPathPatterns("/**") // 静态资源也会被拦截
    7.                 .excludePathPatterns("/", "/login", "/res/**");
    8.     }
    9. }

    可以通过链式调用来指定放行和拦截的路径
    别忘了放行静态资源;