public   class  DBHelper  {    
     public   static  Connection getConnection()  {    
        Connection conn  =   null ;    
         try   {    
            Class.forName( " com.mysql.jdbc.Driver " );    
            conn  =  DriverManager.getConnection( " jdbc:mysql://localhost/ad?useUnicode=true&characterEncoding=GBK&jdbcCompliantTruncation=false " ,    
                     " root " ,  " root " );    
        }   catch  (Exception e)  {    
            e.printStackTrace();    
        }     
         return  conn;    
    }     
}     
   
         /* dao中的方法 */    
     public  List < Adv >  getAllAdvs()  {    
            
        Connection conn  =   null ;    
        ResultSet rs  =   null ;    
        PreparedStatement stmt  =   null ;    
        String sql  =   " select * from adv where id = ? " ;    
        List < Adv >  advs  =   new  ArrayList < Adv > ();    
   
        conn  =  DBHelper.getConnection();    
         if  (conn  !=   null )  {    
             try   {    
                stmt  =  conn.prepareStatement(sql);    
                                stmt.setInt( 1 ,  new  Integer( 1 ));    
                rs  =  stmt.executeQuery();    
   
                 if  (rs  !=   null )  {    
                     while  (rs.next())  {    
                        Adv adv  =   new  Adv();    
                        adv.setId(rs.getLong( 1 ));    
                        adv.setName(rs.getString( 2 ));    
                        adv.setDesc(rs.getString( 3 ));    
                        adv.setPicUrl(rs.getString( 4 ));    
   
                        advs.add(adv);    
                    }     
                }     
            }   catch  (SQLException e)  {    
                e.printStackTrace();    
            }   finally   {    
                 try   {    
                    stmt.close();    
                    conn.close();    
                }   catch  (SQLException e)  {    
                    e.printStackTrace();    
                }     
            }     
        }     
         return  advs;    
    }