java 接口限制访问次数

1. 通过注解的形式实现通用接口访问次数限制

（1）pom.xml文件中引入expiringmap

 <dependency>
      <groupId>net.jodah</groupId>
      <artifactId>expiringmap</artifactId>
      <version>0.5.10</version>
 </dependency>

（2）添加注解

@Documented
@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
public @interface LimitRequest {
    //请求时间
    long time() default 60 * 1000;
    //请求次数
    int count() default Integer.MAX_VALUE;
}

（3）添加注解对应解析类

@Aspect
@Component
public class LimitRequestAspect {
    private static ConcurrentHashMap<String, ExpiringMap<String, Integer>> hashMap = new ConcurrentHashMap<>();

    @Pointcut("@annotation(limitRequest)")
    public void excudeService(LimitRequest limitRequest) {
    }

    @Around("excudeService(limitRequest)")
    public Object doAround(ProceedingJoinPoint pjp, LimitRequest limitRequest) throws Throwable {

        RequestAttributes ra = RequestContextHolder.getRequestAttributes();
        ServletRequestAttributes sra = (ServletRequestAttributes) ra;
        HttpServletRequest request = sra.getRequest();

        ExpiringMap<String, Integer> map = hashMap.getOrDefault(request.getRequestURI(), ExpiringMap.builder().variableExpiration().build());
        Integer count = map.getOrDefault(request.getRemoteAddr(), 0);

        if (count >= limitRequest.count()) {
            throw new BusinessException(500, "访问次数超过限制");
        } else if (count == 0) {
            map.put(request.getRemoteAddr(), count + 1, ExpirationPolicy.CREATED, limitRequest.time(), TimeUnit.MILLISECONDS);
        } else {
            map.put(request.getRemoteAddr(), count + 1);
        }
        hashMap.put(request.getRequestURI(), map);
        Object result = pjp.proceed();

        return result;
    }
}

然后就可以在接口上添加对应的注解@LimitRequest(time=60*1000, count = 3) 来限制时间范围内请求次数了。

2. 针对特殊接口

思路：通过redis 失效时间来控制时间范围内请求次数

String commentKey = String.format("comment:%d:%d", comment.getBusinessId(), comment.getUserId());
Long count = redisTemplate.opsForValue().increment(commentKey);
if (count > 10) {
     throw new BusinessException("发表评论过于频繁,休息下再操作吧~");
   }
redisTemplate.expire(commentKey, 30, TimeUnit.SECONDS);