apollo-portal/src/main/java/com/ctrip/framework/apollo/portal/api/AdminServiceAPI.java/NamespaceBranchAPI/findBranch
class NamespaceBranchAPI:    public NamespaceDTO findBranch(String appId, Env env, String clusterName,
        String namespaceName) {
      return restTemplate.get(env, "/apps/{appId}/clusters/{clusterName}/namespaces/{namespaceName}/branches",
          NamespaceDTO.class, appId, clusterName, namespaceName);
    }