public void t4(){
SqlSession session=factory.openSession();
Orderdetail orderdetail=new Orderdetail();
orderdetail.getOrders_id(4);
int i=session.update("test.UpdateOrderdetail",orderdetail);
System.out.println("更新了"+i+"条");
session.commit();
session.close();
}
无法传值到 mapper.xml中的update 语句中的update orderdetail set items_num=items_num+1 where orders_id=#{orders_id}