SpringBoot配置拦截器

实现 HandlerInterceptor 接口

@Slf4j
public class LoginInterceptor implements HandlerInterceptor {
 
    /**
     * 目标方法执行之前
     * @param request
     * @param response
     * @param handler
     * @return
     * @throws Exception
     */
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
 
        String requestURI = request.getRequestURI();
//        log.info("拦截的请求路径",requestURI);
 
        HttpSession session = request.getSession();
        Object loginUser = session.getAttribute("loginUser");
        if(loginUser != null){
            return true;
        }
        request.setAttribute("msg","请先登录");
        request.getRequestDispatcher("/").forward(request,response);
        return false;
    }
 
    /**
     * 目标方法执行之后
     * @param request
     * @param response
     * @param handler
     * @param modelAndView
     * @throws Exception
     */
    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
 
    }
 
    /**
     * 页面渲染以后
     * @param request
     * @param response
     * @param handler
     * @param ex
     * @throws Exception
     */
    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
 
    }
}

把该拦截器添加到 WebMvcConfigurer

@Configuration
public class AdminWebConfig implements WebMvcConfigurer {
 
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(new LoginInterceptor())
                .addPathPatterns("/**")//所有请求都被拦截，包括静态资源
                .excludePathPatterns("/","/login","/css/**","/fonts/**","/images/**","/js/**");//放行的请求
    }
}

底层原理