jdbc知识

try
{
        con  =
        stmt =
        rs   =
}
catch (Exception e)
{
}
finally
{ 
       try
      {      
        if(rs != null)
        {
           rs.close();
           rs=null;

        }
        if(stat != null)
        {
           stat.close();
           stat=null;

        }
        if(conn != null)
        {
           conn.close();
           conn=null;

        }
       }catch(Exception ignor){        }
}