java代码实现redis 令牌桶限流

以下是基于Java和Redis实现令牌桶限流的代码示例：

import redis.clients.jedis.Jedis;
import redis.clients.jedis.Response;
import redis.clients.jedis.Transaction;

public class RedisTokenBucket {
    private static final String REDIS_KEY = "token_bucket";
    private static final int MAX_TOKENS = 100; // 令牌桶容量
    private static final int REFILL_RATE = 10; // 每秒添加的令牌数

    public boolean allowRequest() {
        Jedis jedis = new Jedis("localhost"); // 连接本地的Redis服务器
        try {
            Transaction transaction = jedis.multi();
            transaction.zremrangeByScore(REDIS_KEY, "-inf", String.valueOf(System.currentTimeMillis() - 1000));
            Response<Long> countResponse = transaction.zcard(REDIS_KEY);
            transaction.zadd(REDIS_KEY, System.currentTimeMillis(), String.valueOf(System.currentTimeMillis()));
            transaction.zrange(REDIS_KEY, 0, -1);
            transaction.expire(REDIS_KEY, 1);
            transaction.exec();

            long count = countResponse.get();
            return count <= MAX_TOKENS;
        } finally {
            jedis.close();
        }
    }
}

该代码使用了Redis的有序集合（Sorted Set）来实现令牌桶限流。每个请求在处理之前都需要从令牌桶中获取一个令牌，只有拿到令牌才能进行其他的业务逻辑。令牌桶的容量为100，每秒添加10个令牌。当令牌桶满时，新的令牌会被丢弃或拒绝。

使用示例：

public class Main {
    public static void main(String[] args) {
        RedisTokenBucket tokenBucket = new RedisTokenBucket();
        for (int i = 0; i < 10; i++) {
            if (tokenBucket.allowRequest()) {
                System.out.println("Request " + (i + 1) + ": Allowed");
            } else {
                System.out.println("Request " + (i + 1) + ": Denied");
            }
        }
    }
}

运行上述代码，将输出类似以下结果：

Request 1: Allowed
Request 2: Allowed
Request 3: Allowed
Request 4: Allowed
Request 5: Allowed
Request 6: Denied
Request 7: Denied
Request 8: Denied
Request 9: Denied
Request 10: Denied