面试平台基于注解的反爬虫机制实现

定义一个注解 @LimitCheck，用于标记需要进行反爬虫检测的方法。

▼
@Target(ElementType.METHOD)
复制代码
@Retention(RetentionPolicy.RUNTIME)
public @interface LimitCheck {
}

创建一个切面类 LimitAspect，在该类中实现反爬虫逻辑。 并且实现了将爬虫用户的ip更新到nacos配置的ip黑名单中。

▼
@Aspect
复制代码
@Component
public class LimitAspect {
    @Resource
    private CounterManager counterManager;

    @Resource
    private UserService userService;

    @Before("@annotation(limitCheck)")
    public void beforeMethod(LimitCheck limitCheck){
        RequestAttributes requestAttributes = RequestContextHolder.currentRequestAttributes();
        HttpServletRequest request = ((ServletRequestAttributes) requestAttributes).getRequest();
        // 显式获取当前登录用户
        User loginUser = userService.getLoginUser(request);
        if (loginUser == null) {
            throw new BusinessException(ErrorCode.NOT_LOGIN_ERROR);
        }

        String ip = IpUtils.getClientIp(request);
        crawlerDetect(loginUser.getId(), ip);
    }

    private void crawlerDetect(long loginUserId, String ip) {
        final int WARN_COUNT = 10;
        final int BAN_COUNT = 20;
        String key = String.format("user:access:%s", loginUserId);
        //计数
        long count = counterManager.incrAndGetCounter(key);
        if (count > BAN_COUNT) {
            //踢下线
            StpUtil.kickout(loginUserId);
            //更新ip黑名单
            updateNacosBlackList(ip);
            throw new BusinessException(ErrorCode.NO_AUTH_ERROR, "访问太频繁，已被封号");
        }
        if (count == WARN_COUNT) {
            throw new BusinessException(110, "警告访问太频繁");
        }
    }

    @Value("${nacos.config.data-id}")
    private String dataId;

    @Value("${nacos.config.server-addr}")
    private String serverAddr;

    @Value("${nacos.config.group}")
    private String group;

    private void updateNacosBlackList(String ip){
        Properties properties = new Properties();
        properties.put("serverAddr", serverAddr);

        try {
            ConfigService configService = NacosFactory.createConfigService(properties);
            String content = configService.getConfig(dataId, group, 5000);
            Yaml yaml = new Yaml();
            Map<String, Object> yamlMap = yaml.load(content);
            List<String> blacklist = (List<String>) yamlMap.get("blackIpList");
            if (!blacklist.contains(ip)) {
                blacklist.add(ip);
            }
            String updatedContent = yaml.dump(yamlMap);
            boolean isPublishOk = configService.publishConfig(dataId, group, updatedContent);
            if (isPublishOk) {
                System.out.println("配置更新成功");
            } else {
                System.out.println("配置更新失败");
            }
        } catch (NacosException e) {
            e.printStackTrace();
        }
    }
}