✨ 添加限流切面，IP工具类，lua脚本，redis配置

spring-boot-demo-ratelimit-redis/src/main/java/com/xkcoding/ratelimit/redis/aspect/RateLimiterAspect.java

+package com.xkcoding.ratelimit.redis.aspect;
+
+import cn.hutool.core.util.StrUtil;
+import com.xkcoding.ratelimit.redis.annotation.RateLimiter;
+import com.xkcoding.ratelimit.redis.util.IpUtil;
+import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+import org.aspectj.lang.ProceedingJoinPoint;
+import org.aspectj.lang.annotation.Around;
+import org.aspectj.lang.annotation.Aspect;
+import org.aspectj.lang.annotation.Pointcut;
+import org.aspectj.lang.reflect.MethodSignature;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.core.annotation.AnnotationUtils;
+import org.springframework.data.redis.core.StringRedisTemplate;
+import org.springframework.data.redis.core.script.RedisScript;
+import org.springframework.stereotype.Component;
+
+import java.lang.reflect.Method;
+import java.time.Instant;
+import java.util.Collections;
+import java.util.concurrent.TimeUnit;
+
+/**
+ * <p>
+ * 限流切面
+ * </p>
+ *
+ * @author yangkai.shen
+ * @date Created in 2019/9/30 10:30
+ */
+@Slf4j
+@Aspect
+@Component
+@RequiredArgsConstructor(onConstructor_ = @Autowired)
+public class RateLimiterAspect {
+    private final static String SEPARATOR = ":";
+    private final static String REDIS_LIMIT_KEY_PREFIX = "limit:";
+    private final StringRedisTemplate stringRedisTemplate;
+    private final RedisScript<Long> limitRedisScript;
+
+    @Pointcut("@annotation(com.xkcoding.ratelimit.redis.annotation.RateLimiter)")
+    public void rateLimit() {
+
+    }
+
+    @Around("rateLimit()")
+    public Object pointcut(ProceedingJoinPoint point) throws Throwable {
+        MethodSignature signature = (MethodSignature) point.getSignature();
+        Method method = signature.getMethod();
+        // 通过 AnnotationUtils.findAnnotation 获取 RateLimiter 注解
+        RateLimiter rateLimiter = AnnotationUtils.findAnnotation(method, RateLimiter.class);
+        if (rateLimiter != null) {
+            String key = rateLimiter.key();
+            // 默认用方法名做限流的 key 前缀
+            if (StrUtil.isBlank(key)) {
+                key = method.getName();
+            }
+            // 最终限流的 key 为 前缀 + IP地址
+            // TODO: 此时需要考虑局域网多用户访问的情况，因此 key 后续需要加上方法参数更加合理
+            key = key + SEPARATOR + IpUtil.getIpAddr();
+
+            long max = rateLimiter.max();
+            long timeout = rateLimiter.timeout();
+            TimeUnit timeUnit = rateLimiter.timeUnit();
+            boolean limited = shouldLimited(key, max, timeout, timeUnit);
+            if (limited) {
+                throw new RuntimeException("手速太快了，慢点儿吧~");
+            }
+        }
+
+        return point.proceed();
+    }
+
+    private boolean shouldLimited(String key, long max, long timeout, TimeUnit timeUnit) {
+        // 最终的 key 格式为：
+        // limit:自定义key:IP
+        // limit:方法名:IP
+        key = REDIS_LIMIT_KEY_PREFIX + key;
+        // 统一使用单位毫秒
+        long ttl = timeUnit.toMillis(timeout);
+        // 当前时间毫秒数
+        long now = Instant.now().toEpochMilli();
+        long expired = now - ttl;
+        // 注意这里必须转为 String,否则会报错 java.lang.Long cannot be cast to java.lang.String
+        Long executeTimes = stringRedisTemplate.execute(limitRedisScript, Collections.singletonList(key), now + "", ttl + "", expired + "", max + "");
+        if (executeTimes != null) {
+            if (executeTimes == 0) {
+                log.error("【{}】在单位时间 {} 毫秒内已达到访问上限，当前接口上限 {}", key, ttl, max);
+                return true;
+            } else {
+                log.info("【{}】在单位时间 {} 毫秒内访问 {} 次", key, ttl, executeTimes);
+                return false;
+            }
+        }
+        return false;
+    }
+}

spring-boot-demo-ratelimit-redis/src/main/java/com/xkcoding/ratelimit/redis/config/RedisConfig.java

+package com.xkcoding.ratelimit.redis.config;
+
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.core.io.ClassPathResource;
+import org.springframework.data.redis.core.script.DefaultRedisScript;
+import org.springframework.data.redis.core.script.RedisScript;
+import org.springframework.scripting.support.ResourceScriptSource;
+
+/**
+ * <p>
+ * Redis 配置
+ * </p>
+ *
+ * @author yangkai.shen
+ * @date Created in 2019/9/30 11:37
+ */
+@Configuration
+public class RedisConfig {
+    @Bean
+    @SuppressWarnings("unchecked")
+    public RedisScript<Long> limitRedisScript() {
+        DefaultRedisScript redisScript = new DefaultRedisScript<>();
+        redisScript.setScriptSource(new ResourceScriptSource(new ClassPathResource("scripts/redis/limit.lua")));
+        redisScript.setResultType(Long.class);
+        return redisScript;
+    }
+}

spring-boot-demo-ratelimit-redis/src/main/java/com/xkcoding/ratelimit/redis/util/IpUtil.java

+package com.xkcoding.ratelimit.redis.util;
+
+import cn.hutool.core.util.StrUtil;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.web.context.request.RequestContextHolder;
+import org.springframework.web.context.request.ServletRequestAttributes;
+
+import javax.servlet.http.HttpServletRequest;
+
+/**
+ * <p>
+ * IP 工具类
+ * </p>
+ *
+ * @author yangkai.shen
+ * @date Created in 2019/9/30 10:38
+ */
+@Slf4j
+public class IpUtil {
+    private final static String UNKNOWN = "unknown";
+    private final static int MAX_LENGTH = 15;
+
+    /**
+     * 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 = ((ServletRequestAttributes) RequestContextHolder.getRequestAttributes()).getRequest();
+        String ip = null;
+        try {
+            ip = request.getHeader("x-forwarded-for");
+            if (StrUtil.isEmpty(ip) || UNKNOWN.equalsIgnoreCase(ip)) {
+                ip = request.getHeader("Proxy-Client-IP");
+            }
+            if (StrUtil.isEmpty(ip) || ip.length() == 0 || UNKNOWN.equalsIgnoreCase(ip)) {
+                ip = request.getHeader("WL-Proxy-Client-IP");
+            }
+            if (StrUtil.isEmpty(ip) || UNKNOWN.equalsIgnoreCase(ip)) {
+                ip = request.getHeader("HTTP_CLIENT_IP");
+            }
+            if (StrUtil.isEmpty(ip) || UNKNOWN.equalsIgnoreCase(ip)) {
+                ip = request.getHeader("HTTP_X_FORWARDED_FOR");
+            }
+            if (StrUtil.isEmpty(ip) || UNKNOWN.equalsIgnoreCase(ip)) {
+                ip = request.getRemoteAddr();
+            }
+        } catch (Exception e) {
+            log.error("IPUtils ERROR ", e);
+        }
+        // 使用代理，则获取第一个IP地址
+        if (!StrUtil.isEmpty(ip) && ip.length() > MAX_LENGTH) {
+            if (ip.indexOf(StrUtil.COMMA) > 0) {
+                ip = ip.substring(0, ip.indexOf(StrUtil.COMMA));
+            }
+        }
+        return ip;
+    }
+}

spring-boot-demo-ratelimit-redis/src/main/resources/application.yml

@@ -2,3 +2,20 @@ server:
   port: 8080
   servlet:
     context-path: /demo
+spring:
+  redis:
+    host: localhost
+    # 连接超时时间（记得添加单位，Duration）
+    timeout: 10000ms
+    # Redis默认情况下有16个分片，这里配置具体使用的分片
+    # database: 0
+    lettuce:
+      pool:
+        # 连接池最大连接数（使用负值表示没有限制） 默认 8
+        max-active: 8
+        # 连接池最大阻塞等待时间（使用负值表示没有限制） 默认 -1
+        max-wait: -1ms
+        # 连接池中的最大空闲连接 默认 8
+        max-idle: 8
+        # 连接池中的最小空闲连接 默认 0
+        min-idle: 0

spring-boot-demo-ratelimit-redis/src/main/resources/scripts/redis/limit.lua

+-- 下标从 1 开始
+local key = KEYS[1]
+local now = tonumber(ARGV[1])
+local ttl = tonumber(ARGV[2])
+local expired = tonumber(ARGV[3])
+-- 最大访问量
+local max = tonumber(ARGV[4])
+
+-- 清除过期的数据
+-- 移除指定分数区间内的所有元素，expired 即已经过期的 score
+-- 根据当前时间毫秒数 - 超时毫秒数，得到过期时间 expired
+redis.call('zremrangebyscore', key, 0, expired)
+-- 获取 zset 中的元素个数
+local current = tonumber(redis.call('zcard', key))
+
+--
+local next = current + 1
+if next > max then
+  -- 达到限流大小 返回 0
+  return 0;
+else
+  -- 往 zset 中添加一个值、得分均为当前时间戳的元素，[value,score]
+  redis.call("zadd", key, now, now)
+  -- 每次访问均重新设置 zset 的过期时间，单位毫秒
+  redis.call("pexpire", key, ttl)
+  return next
+end