依赖

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-aop</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-redis</artifactId>
        <version>1.4.2.RELEASE</version>
    </dependency>
    <dependency>
        <groupId>com.google.guava</groupId>
        <artifactId>guava</artifactId>
        <version>23.0</version>
    </dependency>

自定义注解

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

    // 资源名称，用于描述接口功能
    String name() default "";

    // 资源 key
    String key() default "";

    // key prefix
    String prefix() default "";

    // 时间的，单位秒
    int period();

    // 限制访问次数
    int count();

    // 限制类型
    LimitType limitType() default LimitType.CUSTOMER;
}

枚举类

public enum LimitType {
    // 传统类型
    CUSTOMER,
    // 根据 IP 限制
    IP;
}

异常类

public class LimitAccessException extends Exception {

    private static final long serialVersionUID = -3608667856397125671L;

    public LimitAccessException(String message) {
        super(message);
    }
}

获取ip地址工具类

public class IPUtil {

	private static final String UNKNOWN = "unknown";

	protected IPUtil(){

	}

	/**
	 * 获取 IP地址
	 * 使用 Nginx等反向代理软件， 则不能通过 request.getRemoteAddr()获取 IP地址
	 * 如果使用了多级反向代理的话，X-Forwarded-For的值并不止一个，而是一串IP地址，
	 * X-Forwarded-For中第一个非 unknown的有效IP字符串，则为真实IP地址
	 */
	public static String getIpAddr(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.getRemoteAddr();
		}
		return "0:0:0:0:0:0:0:1".equals(ip) ? "127.0.0.1" : ip;
	}
}

aop实现接口限流，redis执行lua脚本说明如下

tonumber把字符串转换为数字
tostring则把数字转换为字符串。
Lua认为false和nil为假，true 和非nil为真
Redis Incr 命令将 key 中储存的数字值增一。
如果 key 不存在，那么 key 的值会先被初始化为 0
Redis Expire 命令用于设置 key 的过期时间，key 过期后将不再可用。单位以秒计。
主要使用redistempalte封装的execute来实现调用
其中第二个参数为lua脚本中的KEYS[1],后面为可变参数
可变参数即传入我们需要的值，分别对应ARGV[1],ARGV[2]

/**
 * 接口限流
 */
@Slf4j
@Aspect
@Component
public class LimitAspect {

    private final RedisTemplate<String, Serializable> limitRedisTemplate;

    @Autowired
    public LimitAspect(RedisTemplate<String, Serializable> limitRedisTemplate) {
        this.limitRedisTemplate = limitRedisTemplate;
    }

    @Pointcut("@annotation(com.bruce.kls.common.annotation.Limit)")
    public void pointcut() {
        // do nothing
    }

    @Around("pointcut()")
    public Object around(ProceedingJoinPoint point) throws Throwable {
        HttpServletRequest request = ((ServletRequestAttributes) Objects.requireNonNull(RequestContextHolder.getRequestAttributes())).getRequest();

        MethodSignature signature = (MethodSignature) point.getSignature();
        Method method = signature.getMethod();
        Limit limitAnnotation = method.getAnnotation(Limit.class);
        LimitType limitType = limitAnnotation.limitType();
        String name = limitAnnotation.name();
        String key;
        String ip = IPUtil.getIpAddr(request);
        int limitPeriod = limitAnnotation.period();
        int limitCount = limitAnnotation.count();
        switch (limitType) {
            case IP:
                key = ip;
                break;
            case CUSTOMER:
                key = limitAnnotation.key();
                break;
            default:
                key = StringUtils.upperCase(method.getName());
        }
        ImmutableList<String> keys = ImmutableList.of(StringUtils.join(limitAnnotation.prefix() + "_", key, ip));
        String luaScript = buildLuaScript();
        RedisScript<Number> redisScript = new DefaultRedisScript<>(luaScript, Number.class);
        Number count = limitRedisTemplate.execute(redisScript, keys, limitCount, limitPeriod);
        log.info("IP:{} 第 {} 次访问key为 {}，描述为 [{}] 的接口", ip, count, keys, name);
        if (count != null && count.intValue() <= limitCount) {
            return point.proceed();
        } else {
            throw new LimitAccessException("接口访问超出频率限制");
        }
    }

    /**
     * 限流脚本
     * 调用的时候不超过阈值，则执行计算器自加。
     * @return lua脚本
     */
    private String buildLuaScript() {
        return "local c" +
                "\nc = redis.call('get',KEYS[1])" +
                "\nif c and tonumber(c) > tonumber(ARGV[1]) then" +
                "\nreturn c;" +
                "\nend" +
                "\nc = redis.call('incr',KEYS[1])" +
                "\nif tonumber(c) == 1 then" +
                "\nredis.call('expire',KEYS[1],ARGV[2])" +
                "\nend" +
                "\nreturn c;";
    }
}

测试使用

    @GetMapping("/hello")
    @Limit(key = "hello", period = 10, count = 3, name = "测试接口", prefix = "limit")
    public Response<?> hello(){
        return Response.success("ok");
    }