关于数据查找后赋值问题
程序段: 
 String   sqlb= "select   orderid   from   order   where   khno= ' "+khno+ " ' "; 
 ResultSet   rsb=con.executeQuery(sqlb); 
 if(rsb.next()){ 
 String   orderid=rsb.getString(1); 
 rsb.close();}   
 请问为何第四行无法赋值(记录是肯定有的),而改用session.setAttribute( "orderid ",rsb.getString(1));则可以?是我写错了那里?谢谢!
------解决方案--------------------加个.toString()看看?