在hibernate里使用hql语句处理多表查询:
hql语句 from多个对象 as别名,关联,查询,返回
StringBuffer hql = new StringBuffer(
"select mrp,vdp.traincode from MonthReqPlanPO as mrp,VarDictPO as vdp where mrp.varNo=vdp.id");
if (!"".equals(monthReqPlanPO.getId())) {
hql.append(" and mrp.id='").append(monthReqPlanPO.getId()).append(
"'");
}
List list = hibernateDataSource.getByHQL(hql.toString());
return list == null ? new ArrayList() : list ;
在action或者其它层,获取返回list存放的数组对象。按照hql语句的查询列,相应的转换。
List objList;
if (monthReqPlanPOList.size() != 0) {
objList = new ArrayList();
for (int i = 0; i < monthReqPlanPOList.size(); i++) {
Object[] obj = (Object[]) monthReqPlanPOList.get(i);//数组对象
MonthReqPlanPO po = (MonthReqPlanPO) obj[0];//强制转换成PO
po.setRailwayCode((String) obj[1]);//其它查询列 转换,赋值
po.setTrainCode((String) obj[2]);
objList.add(po);
}
}
request.setAttribute("footer", pageListData.getFooter());
monthReqPlanListActionForm.setMonthReqPlanPOList(objList);