redis实现API限流

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我是靠谱客的博主微笑指甲油，最近开发中收集的这篇文章主要介绍redis实现API限流，觉得挺不错的，现在分享给大家，希望可以做个参考。

概述

思路

自定义注解定义限流片段时间和最大请求个数
拦截器拦截所有请求，如果发现使用了限流注解的API，查看redis里是否记录了该接口的请求次数，如果有，就判断没有超过自定义注解的最大阈值，达到阈值就拦截该请求，否则请求次数加1并放行
使用到redis key自过过期方法，自增量方法

springboot示例代码

注解

@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
public @interface AccessLimit {

    int seconds() default 1;
    int maxCount() default 20;

}

拦截器

@Slf4j
public class AccessLimitInterceptor implements HandlerInterceptor {

    @Autowired
    private RedisUtil redisUtil;

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        if(handler instanceof HandlerMethod){
            HandlerMethod handlerMethod = (HandlerMethod) handler;
            AccessLimit accessLimit = handlerMethod.getMethodAnnotation(AccessLimit.class);
            if(accessLimit == null) return true;
            int seconds = accessLimit.seconds();
            int maxCount = accessLimit.maxCount();
            String url = request.getRequestURI();
            String key = RedisKey.accessLimit(url);
            if(redisUtil.hasKey(key)){
                Integer count = redisUtil.get(key);
                if(count == null) return true;
                if(count >= maxCount) throw new APIException(APICode.SYSTEM_BUSY);
                redisUtil.increment(key, 1);
            }else {
                redisUtil.set(key, 1, seconds);
            }
        }
        return true;
    }

}

配置

@Configuration
public class WebConfig implements WebMvcConfigurer {

    @Bean
    public AccessLimitInterceptor accessLimitInterceptor(){
        return new AccessLimitInterceptor();
    }

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registration = registry.addInterceptor(accessLimitInterceptor());
        registration.addPathPatterns("/**");
        registration.excludePathPatterns(
                "/",
                "/**/swagger-resources/**",
                "/**/*.html",
                "/**/*.js",
                "/**/*.css"
        );
    }
}