apollo-biz/src/main/java/com/ctrip/framework/apollo/biz/service/AppNamespaceService.java/AppNamespaceService/findPublicNamespaceByName
class AppNamespaceService:  public AppNamespace findPublicNamespaceByName(String namespaceName) {
    Preconditions.checkArgument(namespaceName != null, "Namespace must not be null");
    return appNamespaceRepository.findByNameAndIsPublicTrue(namespaceName);
  }