php PDO setFetchMode

<?php
/**
*File name: PDO.php
*Created by: ShowJoy
*Contact: 734578348@qq.com, xubiao522@gmail.com
*Last modified: 2014-5-27
*/
class User{
    private $id;
    private $name;//这里必须注意取名必须和从数据库里返回数据的列名一致
    
    public function getUserName(){
        return $this->name;
    }
    
}
try{
    $dsn = "mysql:dbname=test;host=localhost";// Data source name
    $pdo = new PDO($dsn, 'root', 'xubiao');//创建PDO对象
    
    $res = $pdo->query('select * from users');
    $res->setFetchMode(PDO::FETCH_CLASS, 'User');//记录的获取模式，将返回的记录转换成具体类的对象
    
    while(!!$row = $res->fetch()){
        //$row就是User类的对象
        echo $row->getUserName();
    }
    
    
    
    unset($pdo); //关闭数据库连接
}catch (PDOException $e){
    echo '<p class="error">An error occurrend: '.$e->getMessage().'</p>';
}
?>