Quick use of springBoot interceptor

1. Configure the interceptor

To configure your own interceptor, you need to inherit HandlerInterceptor

public class LoginInterceptor implements HandlerInterceptor {
    
    

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
    
    
       //1.获取session
        HttpSession session = request.getSession();
        //2.获取session中的用户
        Object user = session.getAttribute("user");
        //3.判断用户是否存在
        if(user == null){
    
    
              //4.不存在，拦截，返回401状态码
              response.setStatus(401);
              return false;
        }
        //5.存在，保存用户信息到Threadlocal
        UserHolder.saveUser((User)user);
        //6.放行
        return true;
    }
}

2. Let the interceptor take effect

To make the interceptor take effect, we need to add the interceptor we wrote to the interceptor registry of WebMvc

@Configuration
public class MvcConfig implements WebMvcConfigurer {
    
    

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
    
    
        // 登录拦截器
        registry.addInterceptor(new LoginInterceptor())
                .excludePathPatterns(
                        "/shop/**",
                        "/voucher/**",
                        "/shop-type/**",   //配置哪些不需要被拦截
                        "/upload/**",
                        "/blog/hot",
                        "/user/code",
                        "/user/login"
                ).order(1); //order的作用是指定拦截器的拦截顺序，数字越小越先拦截。
        // token刷新的拦截器
        registry.addInterceptor(new RefreshTokenInterceptor(stringRedisTemplate)).addPathPatterns("/**").order(0);
    }
}