GAP使用JDO查询
注意事项：
1、与条件使用 &&
2、过滤条件queryTemplate 不能加上排序order by语句。解决方法是使用query.setOrdering("orderDate desc");
public List<FanOrder> queryByUsername(String username,String startDate,String endDate){List<FanOrder> orders = null;Query query = null;try {String queryTemplate = "",filter="";if (!username.equals("")){queryTemplate = "username == "%s" && orderDate >= "%s" && orderDate <= "%s" ";filter = String.format(queryTemplate,username,startDate, endDate);}else{queryTemplate = "orderDate >= "%s" && orderDate <= "%s" ";filter = String.format(queryTemplate,startDate, endDate);}query = pm.newQuery(FanOrder.class,filter);query.setOrdering("orderDate desc"); orders = (List<FanOrder>) query.execute();} catch (RuntimeException e) {e.printStackTrace();}finally { query.closeAll(); }return orders;}