apollo-core/src/main/java/com/ctrip/framework/apollo/core/MetaDomainConsts.java/MetaDomainConsts/getMetaServerAddress
class MetaDomainConsts:  public static String getMetaServerAddress(Env env) {
    if (!metaServerAddressCache.containsKey(env)) {
      initMetaServerAddress(env);
    }

    return metaServerAddressCache.get(env);
  }