C++技术中的大数据处理：如何采用流处理技术处理大数据流？

// 头文件
#include <kafka/apache_kafka.h>
#include <thread>
#include <atomic>

// 定义原子平均值计数器
std::atomic<double> avg_count(0.0);

// 流处理消费者线程
void consume_thread(const std::string& topic, rd_kafka_t* rk) {
  // 创建消费者组
  rd_kafka_consumer_group_t* consumer_group =
      rd_kafka_consumer_group_join(rk, topic.c_str(),
                                  rd_kafka_topic_partition_list_new(1), NULL);

  while (true) {
    // 订阅主题
    rd_kafka_message_t* message;
    rd_kafka_resp_err_t consumer_err =
        rd_kafka_consumer_group_poll(consumer_group, 10000, &message);
    if (consumer_err == RD_KAFKA_RESP_ERR__PARTITION_EOF) {
      rd_kafka_consumer_group_unjoin(consumer_group);
      rd_kafka_consumer_group_destroy(consumer_group);
      return;
    } else if (consumer_err != RD_KAFKA_RESP_ERR_NO_ERROR) {
      std::cerr << "Consumer error: " << rd_kafka_err2str(consumer_err) << "\n";
      continue;
    }

    // 提取并处理数据
    if (message) {
      // 提取值
      const char* message_str = static_cast<const char*>(message->payload);
      int value = std::atoi(message_str);

      // 更新原子平均值计数器
      avg_count += (static_cast<double>(value) - avg_count) /
                     (avg_count.fetch_add(1) + 1);

      if (avg_count >= 1e6) {
        std::cout << "Average: " << avg_count << "\n";
      }
    }

    // 提交偏移量
    rd_kafka_message_destroy(message);
  }
}

int main() {
  // 初始化 Kafka 实例
  rd_kafka_t* rk = rd_kafka_new(RD_KAFKA_CONSUMER, NULL, NULL, NULL);
  if (!rk) {
    std::cerr << "Failed to initialize Kafka instance\n";
    return 1;
  }

  // 配置 Kafka 实例
  char error_str[512];
  if (rd_kafka_conf_set(rk, "bootstrap.servers", "localhost:9092",
                          error_str, sizeof(error_str)) != RD_KAFKA_CONF_OK) {
    std::cerr << "Failed to set Kafka configuration: " << error_str << "\n";
    rd_kafka_destroy(rk);
    return 1;
  }

  // 创建流处理消费者线程
  std::thread consumer_thr(consume_thread, "test-topic", rk);

  // 等待消费者线程
  consumer_thr.join();

  // 销毁 Kafka 实例
  rd_kafka_destroy(rk);

  return 0;
}