public ResultSet getRset(String sqlstr)
{  
   try
    {
        ct=this.getConn();
        pm=ct.prepareStatement(sqlstr);
        rs=pm.executeQuery();
        closeall();
    }
   catch(Exception e)
       {e.printStackTrace();}
  finally
   {
   return rs;
   }
}


public void closeall()
{ 
try{

  if(this.rs!=null){rs.close();this.rs=null;}
  if(this.pm!=null){pm.close();this.pm=null;}
  if(this.ct!=null){ct.close();this.ct=null;}
}
catch(Exception e)
{e.printStackTrace();}
}