扩展类：PayableBillControllerBeanEx
public class PayableBillControllerBeanEx extends com.kingdee.eas.fm.nt.app.PayableBillControllerBean

在扩展类中覆盖方法不起作用：
protected IObjectPK _addnew(Context ctx, IObjectValue model) throws BOSException, EASBizException
{
PayableBillInfo billInfo = (PayableBillInfo)model;
billInfo.setDraftNumber(billInfo.getNumber());
IObjectPK billPK = super._addnew(ctx, billInfo);

}

哪位仁兄帮忙解释一下呗。