文章目录

• 一、编写一个拦截器实现HandlerInterceptor 接口
• 二、将拦截器添加到容器中(实现WebMvcConfigurer的addInterceptors方法)
• 三、制定拦截规则

一、编写一个拦截器实现HandlerInterceptor 接口

//登录检查
public class Logininterceptor implements HandlerInterceptor {
    //目标方法执行前
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        HttpSession session = request.getSession();
        Object loginUser = session.getAttribute("loginUser");
        if (loginUser != null) {
            return true;
        }
        //拦截住未登录，跳转登录页
        response.sendRedirect("/");
        session.setAttribute("msg","请先登录!");
        return  false;
    }

    //目标方法执行后
    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {

    }

    //页面渲染以后
    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {

    }
}

执行顺序：preHandle->目标方法mainPage->postHandle->afterCompletion

二、将拦截器添加到容器中(实现WebMvcConfigurer的addInterceptors方法)

@Configuration
public class AdminWebConfig implements WebMvcConfigurer {
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(new Logininterceptor())
                .addPathPatterns("/**")            //静态资源也会拦截
                .excludePathPatterns("/","/login","/css/**","/fonts/**","/images/**","/js/**");//放行

    }
}

三、制定拦截规则

注意静态资源也会被拦截，要设置通过。

                .addPathPatterns("/**")            //静态资源也会拦截
                .excludePathPatterns("/","/login","/css/**","/fonts/**","/images/**","/js/**");//放行