apollo-portal/src/main/java/com/ctrip/framework/apollo/openapi/service/ConsumerService.java/ConsumerService/getConsumerTokenByAppId
class ConsumerService:  public ConsumerToken getConsumerTokenByAppId(String appId) {
    Consumer consumer = consumerRepository.findByAppId(appId);
    if (consumer == null) {
      return null;
    }

    return consumerTokenRepository.findByConsumerId(consumer.getId());
  }