apollo-portal/src/main/java/com/ctrip/framework/apollo/portal/api/AdminServiceAPI.java/AdminServiceAPI/createNamespace
class AdminServiceAPI:    public NamespaceDTO createNamespace(Env env, NamespaceDTO namespace) {
      return restTemplate
          .post(env, "apps/{appId}/clusters/{clusterName}/namespaces", namespace, NamespaceDTO.class,
              namespace.getAppId(), namespace.getClusterName());
    }