DAO层代码!求教!
private static final String selectPRODUCTBUYMOUNT = "select product_buymount from dg_list where order_id=?";
public static int PRODUCTBUYMOUNT(int ORDER_ID){
try {
ConnManage.openTransaction();
con = ConnectionSource.getConnection();
PreparedStatement pst = con.prepareStatement(selectPRODUCTBUYMOUNT);
pst.setInt(1, ORDER_ID);
ResultSet rst=null;
rst = pst.executeQuery();
while(rst.next()){
// return rst.getInt(1); //返回ORDER_ID
int PRODUCT_BUYMOUNT = rst.getInt("PRODUCT_BUYMOUNT");
return PRODUCT_BUYMOUNT;
}
pst.close();
con.commit();
} catch (SQLException e) {
e.printStackTrace();
return -1;
}
public static void main(String[] args){
// System.out.println(PRODUCTBUYMOUNT);
System.out.println(BuylistDAO.PRODUCTBUYMOUNT(4));
}
现在的情况是
我直接写order_id=4,在数据库中用sql语句查询结果是5,
但是我按照以上的代码来运行的话,打印-1;
说明while(rst.next())里面的根本就没执行。不知道什么原因,求教!!!