apollo-adminservice/src/main/java/com/ctrip/framework/apollo/adminservice/controller/AppNamespaceController.java/AppNamespaceController/delete
class AppNamespaceController:  @DeleteMapping("/apps/{appId}/appnamespaces/{namespaceName:.+}")
  public void delete(@PathVariable("appId") String appId, @PathVariable("namespaceName") String namespaceName,
      @RequestParam String operator) {
    AppNamespace entity = appNamespaceService.findOne(appId, namespaceName);
    if (entity == null) {
      throw new BadRequestException("app namespace not found for appId: " + appId + " namespace: " + namespaceName);
    }
    appNamespaceService.deleteAppNamespace(entity, operator);
  }