String group = StringUtil.clean(param.getGroup())==null
?SystemParam.DEFAULT_GROUP_NAME:param.getGroup();
ListPage<SystemParam> page = new ListPage<SystemParam>(1);
SearchCondition sc = new SearchCondition();
sc.equal("group", group ).equal("name",param.getName() );
page = dao.list(page, sc);
SystemParam exists = (page.getList()==null||page.getList().isEmpty())
?null:page.getList().get(0);