apollo-portal/src/main/java/com/ctrip/framework/apollo/portal/service/ConfigsExportService.java/ConfigsExportService/exportData
class ConfigsExportService:  public void exportData(OutputStream outputStream, List<Env> exportEnvs) {
    if (CollectionUtils.isEmpty(exportEnvs)) {
      exportEnvs = portalSettings.getActiveEnvs();
    }

    exportApps(exportEnvs, outputStream);
  }