apollo-adminservice/src/main/java/com/ctrip/framework/apollo/adminservice/controller/ItemController.java/ItemController/delete
class ItemController:  @PreAcquireNamespaceLock
  @DeleteMapping("/items/{itemId}")
  public void delete(@PathVariable("itemId") long itemId, @RequestParam String operator) {
    Item entity = itemService.findOne(itemId);
    if (entity == null) {
      throw new NotFoundException("item not found for itemId " + itemId);
    }
    itemService.delete(entity.getId(), operator);

    Namespace namespace = namespaceService.findOne(entity.getNamespaceId());

    Commit commit = new Commit();
    commit.setAppId(namespace.getAppId());
    commit.setClusterName(namespace.getClusterName());
    commit.setNamespaceName(namespace.getNamespaceName());
    commit.setChangeSets(new ConfigChangeContentBuilder().deleteItem(entity).build());
    commit.setDataChangeCreatedBy(operator);
    commit.setDataChangeLastModifiedBy(operator);
    commitService.save(commit);
  }