利用spring如何实现接口限流

利用spring如何实现接口限流

1.创建自定义注解

**
 * 限流注解
 */
@Inherited
@Documented
@Target({ElementType.FIELD, ElementType.TYPE, ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
public @interface AccessLimit {
    //限流唯一标识
    String key() default "";

    //限流时间
    int time();

    //限流次数
    int count();

}

创建限流配置类

/**
 * 注解拦截
 */
@Slf4j
@Aspect
@Configuration
public class AccessLimitConfig {
    @Autowired
    private RedisTemplate<String, Serializable> redisTemplate;
    @Autowired
    private DefaultRedisScript<Number> redisScript;

    /**
     * 执行redis的具体方法，限制method，保证没有其他的东西进来
     *
     * @return
     */
    @Around("execution(* com.mayday.auth.controller ..*(..) )")
    public Object interceptor(ProceedingJoinPoint joinPoint) throws Throwable {
        MethodSignature signature = (MethodSignature) joinPoint.getSignature();
        Method method = signature.getMethod();
        Class<?> targetClass = method.getDeclaringClass();
        AccessLimit accessLimit = method.getAnnotation(AccessLimit.class);
        if (accessLimit != null) {
            //获取request对象
            HttpServletRequest request = ((ServletRequestAttributes) Objects.requireNonNull(RequestContextHolder.getRequestAttributes())).getRequest();
            String ipAddr = IpUtils.getIpAddr(request);
            String string = ipAddr + "-" + targetClass.getName() + "- " + method.getName() + "-" + accessLimit.key();
            List<String> keys = Collections.singletonList(string);
            Number number = redisTemplate.execute(redisScript, keys, accessLimit.count(), accessLimit.time());
            if (number != null && number.intValue() != 0 && number.intValue() <= accessLimit.count()) {
                return joinPoint.proceed();
            }
        } else {
            return joinPoint.proceed();
        }
        return new Result(false, StatusCode.REPEAT_OPERATE);
    }
}

3. 创建切面类

/**
 * 限流配置
 */
@Slf4j @Component
public class AccessLimitAspect {
    /**
     * 读取限流脚本
     *
     * @return
     */
    @Bean
    public DefaultRedisScript<Number> redisLuaScript() {
        DefaultRedisScript<Number> redisScript = new DefaultRedisScript<>();
        redisScript.setScriptSource(new ResourceScriptSource(new ClassPathResource("redisLimit.lua")));
        //返回类型
        redisScript.setResultType(Number.class);
        return redisScript;
    }
    /**
     * RedisTemplate
     *
     * @return
     */
    @Bean
    public RedisTemplate<String, Serializable> limitRedisTemplate(LettuceConnectionFactory redisConnectionFactory) {
        RedisTemplate<String, Serializable> template = new RedisTemplate<>();
        template.setKeySerializer(new StringRedisSerializer());
        template.setValueSerializer(new GenericJackson2JsonRedisSerializer());
        template.setConnectionFactory(redisConnectionFactory);
        return template;
    }

}

Lua脚本

--Lua脚本

--IP限流Lua脚本
--- 限流KEY资源唯一标识
local key = "rate.limit:" .. KEYS[1]
--- 时间窗最大并发数
local limit = tonumber(ARGV[1])
--- -过期时间
local expire_time = ARGV[2]

local is_exists = redis.call("EXISTS", key)
if is_exists == 1 then
    if redis.call("INCR", key) > limit then
        return 0
    else
        return 1
    end
else
    redis.call("SET", key, 1)
    redis.call("EXPIRE", key, expire_time)
    return 1
end