springboot 登录拦截器

1.定义一个视图解析器

@Configuration
public class MyMvcConfig implements WebMvcConfigurer {
    /**
     * 添加视图解析
     */
    //// 无用代码，暂时注释，之后删除
//    @Override
//    public void addViewControllers(ViewControllerRegistry registry) {
//        registry.addViewController("/").setViewName("index");
//        registry.addViewController("/index.html").setViewName("index");
//        registry.addViewController("/login.html").setViewName("login");
//        registry.addViewController("/login").setViewName("login");
//        registry.addViewController("/personal_center").setViewName("personal_center");
//    }

    /**
     * 注册拦截器
     */
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
//        registry.addInterceptor(new LoginInterceptor())
//                .addPathPatterns("/**").excludePathPatterns("/index","/","/login","/user/login","/static/**","/druid/*");
        InterceptorRegistration addInterceptor = registry.addInterceptor(new LoginInterceptor());
        // 排除配置
        addInterceptor.excludePathPatterns("/index");
        addInterceptor.excludePathPatterns("/login");
        addInterceptor.excludePathPatterns("/");
        addInterceptor.excludePathPatterns("/error");
        addInterceptor.excludePathPatterns("/static/**");
        addInterceptor.excludePathPatterns("/pdb/tuba/**");
        addInterceptor.excludePathPatterns("/test/**");
        // 拦截配置
        addInterceptor.addPathPatterns("/**");
    }

    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
        registry.addResourceHandler("/static/**").addResourceLocations("classpath:/static/");
    }
}

2.定义一个拦截器

/**
 * 登录拦截器
 */
public class LoginInterceptor implements HandlerInterceptor {

    /**
     * 在请求处理之前进行调用（Controller方法调用之前）
     */
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response,
                             Object object) throws ServletException, IOException {
        Object user = request.getSession().getAttribute("user");
        if (user==null){
            request.setAttribute("error","当前处于未登录状态!");
//            request.getRequestDispatcher("/").forward(request,response);
            response.sendRedirect("/index");
            return false;
        }else {
            return true;
        }
    }

    /**
     * 请求处理之后进行调用，但是在视图被渲染之前（Controller方法调用之后）
     */
    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response,
                           Object object, ModelAndView mv)
            throws Exception {
        // TODO Auto-generated method stub
    }

    /**
     * 在整个请求结束之后被调用，也就是在DispatcherServlet 渲染了对应的视图之后执行
     * （主要是用于进行资源清理工作）
     */
    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response,
                                Object object, Exception ex)
            throws Exception {
        // TODO Auto-generated method stub
    }
}