apollo-portal/src/main/java/com/ctrip/framework/apollo/portal/component/ItemsComparator.java/ItemsComparator/copyItem
class ItemsComparator:  private ItemDTO copyItem(ItemDTO sourceItem){
    ItemDTO copiedItem = new ItemDTO();
    copiedItem.setKey(sourceItem.getKey());
    copiedItem.setValue(sourceItem.getValue());
    copiedItem.setComment(sourceItem.getComment());
    return copiedItem;

  }