apollo-adminservice/src/main/java/com/ctrip/framework/apollo/adminservice/controller/NamespaceBranchController.java/NamespaceBranchController/loadNamespaceBranch
class NamespaceBranchController:  @GetMapping("/apps/{appId}/clusters/{clusterName}/namespaces/{namespaceName}/branches")
  public NamespaceDTO loadNamespaceBranch(@PathVariable String appId, @PathVariable String clusterName,
                                          @PathVariable String namespaceName) {

    checkNamespace(appId, clusterName, namespaceName);

    Namespace childNamespace = namespaceBranchService.findBranch(appId, clusterName, namespaceName);
    if (childNamespace == null) {
      return null;
    }

    return BeanUtils.transform(NamespaceDTO.class, childNamespace);
  }