apollo-portal/src/main/java/com/ctrip/framework/apollo/portal/component/txtresolver/FileTextResolver.java/FileTextResolver/createItem
class FileTextResolver:  private ItemDTO createItem(long namespaceId, long itemId, String value) {
    ItemDTO item = new ItemDTO();
    item.setId(itemId);
    item.setNamespaceId(namespaceId);
    item.setValue(value);
    item.setLineNum(1);
    item.setKey(ConfigConsts.CONFIG_FILE_CONTENT_KEY);
    return item;
  }