apollo-portal/src/main/java/com/ctrip/framework/apollo/portal/api/AdminServiceAPI.java/NamespaceAPI/countPublicAppNamespaceAssociatedNamespaces
class NamespaceAPI:    public int countPublicAppNamespaceAssociatedNamespaces(Env env, String publicNamesapceName) {
      Integer count =
          restTemplate.get(env, "/appnamespaces/{publicNamespaceName}/associated-namespaces/count", Integer.class,
              publicNamesapceName);

      return count == null ? 0 : count;
    }