springboot Redis + HandlerInerceptor实现接口防刷

Posted 2020-12-12 LifeOfCoding

说明

代码剥离自其他老哥的项目，项目地址——https://github.com/wangzaiplus/springboot/tree/wxw
再此记录下来以备不时之需

创建注解

/**
 * 在需要保证 接口防刷限流 的Controller的方法上使用此注解
 */
@Target({ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
public @interface AccessLimit {

    int maxCount();// 最大访问次数

    int seconds();// 固定时间, 单位: s

}

配置拦截器

实现 HandlerInterceptor 类，该类包含三个方法：

• preHanle(HttpServletRequest request, HttpServletResponse response, Object handler)
  执行 handler 前调用

• postHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, ModelAndView modelAndView)
  在处理完业务，返回视图前调用

• afterCompletion(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e)
  所有东西完成后调用

此处只需要实现 preHandle

/**
 * 接口防刷限流拦截器
 */
public class AccessLimitInterceptor implements HandlerInterceptor {

    @Autowired
    private JedisUtil jedisUtil;

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) {
        //判断是否Handler方法
        if (!(handler instanceof HandlerMethod)) {
            return true;
        }
        
        HandlerMethod handlerMethod = (HandlerMethod) handler;
        Method method = handlerMethod.getMethod();

        //获取该方法上的AccessLimit注解
        AccessLimit annotation = method.getAnnotation(AccessLimit.class);
        if (annotation != null) {
            check(annotation, request);
        }
        return true;
    }
    
    //检查是否可访问
    private void check(AccessLimit annotation, HttpServletRequest request) {
        int maxCount = annotation.maxCount();
        int seconds = annotation.seconds();

        StringBuilder sb = new StringBuilder();

        //按规则拼接字符串，查看redis是否包含该key
        sb.append(Constant.Redis.ACCESS_LIMIT_PREFIX).append(IpUtil.getIpAddress(request)).append(request.getRequestURI());
        String key = sb.toString();

        Boolean exists = jedisUtil.exists(key);
        if (!exists) {
            jedisUtil.set(key, String.valueOf(1), seconds);
        } else {
            int count = Integer.valueOf(jedisUtil.get(key));
            if (count < maxCount) {
                Long ttl = jedisUtil.ttl(key);
                if (ttl <= 0) {
                    jedisUtil.set(key, String.valueOf(1), seconds);
                } else {
                    jedisUtil.set(key, String.valueOf(++count), ttl.intValue());
                }
            } else {
                throw new ServiceException(ResponseCode.ACCESS_LIMIT.getMsg());
            }
        }
    }

工具类

JedisUtil:

@Component
@Slf4j
public class JedisUtil {

    @Autowired(required = false)
    private JedisPool jedisPool;

    private Jedis getJedis() {
        return jedisPool.getResource();
    }

    /**
     * 设值
     *
     * @param key
     * @param value
     * @return
     */
    public String set(String key, String value) {
        Jedis jedis = null;
        try {
            jedis = getJedis();
            return jedis.set(key, value);
        } catch (Exception e) {
            log.error("set key: {} value: {} error", key, value, e);
            return null;
        } finally {
            close(jedis);
        }
    }

    /**
     * 设值
     *
     * @param key
     * @param value
     * @param expireTime 过期时间, 单位: s
     * @return
     */
    public String set(String key, String value, int expireTime) {
        Jedis jedis = null;
        try {
            jedis = getJedis();
            return jedis.setex(key, expireTime, value);
        } catch (Exception e) {
            log.error("set key:{} value:{} expireTime:{} error", key, value, expireTime, e);
            return null;
        } finally {
            close(jedis);
        }
    }

    /**
     * 设值
     *
     * @param key
     * @param value
     * @return
     */
    public Long setnx(String key, String value) {
        Jedis jedis = null;
        try {
            jedis = getJedis();
            return jedis.setnx(key, value);
        } catch (Exception e) {
            log.error("set key:{} value:{} error", key, value, e);
            return null;
        } finally {
            close(jedis);
        }
    }

    /**
     * 取值
     *
     * @param key
     * @return
     */
    public String get(String key) {
        Jedis jedis = null;
        try {
            jedis = getJedis();
            return jedis.get(key);
        } catch (Exception e) {
            log.error("get key:{} error", key, e);
            return null;
        } finally {
            close(jedis);
        }
    }

    /**
     * 删除key
     *
     * @param key
     * @return
     */
    public Long del(String key) {
        Jedis jedis = null;
        try {
            jedis = getJedis();
            return jedis.del(key.getBytes());
        } catch (Exception e) {
            log.error("del key:{} error", key, e);
            return null;
        } finally {
            close(jedis);
        }
    }

    /**
     * 判断key是否存在
     *
     * @param key
     * @return
     */
    public Boolean exists(String key) {
        Jedis jedis = null;
        try {
            jedis = getJedis();
            return jedis.exists(key.getBytes());
        } catch (Exception e) {
            log.error("exists key:{} error", key, e);
            return null;
        } finally {
            close(jedis);
        }
    }

    /**
     * 设值key过期时间
     *
     * @param key
     * @param expireTime 过期时间, 单位: s
     * @return
     */
    public Long expire(String key, int expireTime) {
        Jedis jedis = null;
        try {
            jedis = getJedis();
            return jedis.expire(key.getBytes(), expireTime);
        } catch (Exception e) {
            log.error("expire key:{} error", key, e);
            return null;
        } finally {
            close(jedis);
        }
    }

    /**
     * 获取剩余时间
     *
     * @param key
     * @return
     */
    public Long ttl(String key) {
        Jedis jedis = null;
        try {
            jedis = getJedis();
            return jedis.ttl(key);
        } catch (Exception e) {
            log.error("ttl key:{} error", key, e);
            return null;
        } finally {
            close(jedis);
        }
    }

    private void close(Jedis jedis) {
        if (null != jedis) {
            jedis.close();
        }
    }

}

IpUtil:

public class IpUtil {

    /**
     * 获取客户端真实ip地址
     *
     * @param request
     * @return
     */
    public static String getIpAddress(HttpServletRequest request) {
        String ip = request.getHeader("x-forwarded-for");

        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getHeader("Proxy-Client-IP");
        }

        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getHeader("WL-Proxy-Client-IP");
        }

        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getHeader("HTTP_CLIENT_IP");
        }

        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getHeader("HTTP_X_FORWARDED_FOR");
        }

        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getRemoteAddr();
        }

        return ip;
    }

}