apollo-core/src/main/java/com/ctrip/framework/apollo/core/utils/DNSUtil.java/DNSUtil/resolve
class DNSUtil:  public static List<String> resolve(String domainName) throws UnknownHostException {
    List<String> result = new ArrayList<>();

    InetAddress[] addresses = InetAddress.getAllByName(domainName);
    if (addresses != null) {
      for (InetAddress addr : addresses) {
        result.add(addr.getHostAddress());
      }
    }

    return result;
  }