SpringBoot之拦截器优雅实现登录权限拦截

在上一章节中我们讲解了Spring Boot中拦截器的基本使用步骤

本次我们将使用拦截器来实现 登录状态的拦截判断需求

OK，直接上代码：

首先我们实现一个AdminLoginInterInterceptor 拦截器，在用户访问管理端的url时，判断是否为管理员

  @Component
  public class AdminLoginInterceptor implements HandlerInterceptor {
      public static String LOGIN_FLAG = "admin";
      private void printMsg(String msg) {
          System.out.println("[AdminLoginInterceptor] " +msg);

      }

      @Override
      public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
          printMsg("preHandle");

          HttpSession session = request.getSession(true);
          if (session.getAttribute(LOGIN_FLAG) != null) {
              printMsg("已登录");
              return true;
          }
          // 重定向到登录页面
          response.sendRedirect(Utils.getHostPath(request) + "/admin/loginPage");
          return true;
      }
      @Override
      public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,
                             ModelAndView modelAndView) throws Exception {
          printMsg("postHandle");
      }

      @Override
      public void afterCompletion(HttpServletRequest request, HttpServletResponse response,
                                  Object handler, Exception exception) throws Exception {
          printMsg("afterCompletion");

      }
  }

拦截器写好了，此时就是要将我们的拦截器与Spring关联上并告知 如何调用了

通过实现一个WebMvcConfigurer，然后通过addInterceptors方法参数中的注册器注册拦截器

  @Component
  public class ProductServiceInterceptorAppConfig implements WebMvcConfigurer {
     @Autowired
     PathInterceptor pathInterceptor;

     @Autowired
     AdminLoginInterceptor adminLoginInterceptor;

     @Override
     public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(adminLoginInterceptor).addPathPatterns("/admin/**")
                .excludePathPatterns("/admin/login","/admin/loginPage");

     }
  }

在login的时候我们将登陆成功后的信息存入session中 通过LOGIN_FLAG作为key即可