springboot限流注解

我们在工作中有些接口访问量过大为了保证服务的正常运行可以增加限流

第一步引入aop和redis

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-aop</artifactId>
        </dependency>
		<dependency>
   			<groupId>org.springframework.boot</groupId>
    		<artifactId>spring-boot-starter-data-redis</artifactId>
		</dependency>

第二步注解实现


@Target(value = ElementType.METHOD)
@Retention(value = RetentionPolicy.RUNTIME)
public @interface Limit {
    /**
     * 资源的key,唯一
     * 作用：不同的接口，不同的流量控制
     */
    String key() default "";

    /**
     * 最大访问限制次数
     */
    double permitsPerSecond();

    /**
     * 得不到令牌的提示语
     */
    String msg() default "访问过多,请稍后再试.";
}

第三步编写aop切面实现限流

@Slf4j
@Aspect
@Component
public class RateLimiterAspect {

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Around("@annotation(com.nms.common.utils.Limit)")
    public Object around(ProceedingJoinPoint joinPoint) throws Throwable {
        MethodSignature signature = (MethodSignature) joinPoint.getSignature();
        Method method = signature.getMethod();
        Limit limit = method.getAnnotation(Limit.class);
        if (limit != null) {
            String key = "rate_limit:" + limit.key();
            // 获取当前计数
            String countStr = stringRedisTemplate.opsForValue().get(key);
            long count = countStr == null ? 0 : Long.parseLong(countStr);
            if (count >= limit.permitsPerSecond()) {
                log.info("限流生效 - 方法: {}, key: {}", method.getName(), key);
                throw new ServiceException(limit.msg());
            }
            // 计数器加1，并设置1秒过期
            stringRedisTemplate.opsForValue().increment(key);
            stringRedisTemplate.expire(key, 1, TimeUnit.SECONDS);
        }
        return joinPoint.proceed();
    }
}

第四步使用注解

    @Limit(
            key = "getByOrderNo",
            permitsPerSecond = 1,
            msg = "当前访问较多，请稍后再试！"
    )
    @GetMapping("getByOrderNo")
    public RestResponse getByOrderNo(String orderNo) {
        Map<String, Object> info = checkService.info(orderNo);
        return RestResponse.success().put(info);
    }