[PHP] 使用适配器模式处理数据库对象

<?php
//类适配器
class PDOAdapter extends PDO{
    private $dsn = null;
    private $username = null;
    private $password = null;
    private $timeout = 30;
    private $charset = "utf8";
    private $options = array(
        PDO::ATTR_AUTOCOMMIT            => true,
        PDO::ATTR_ERRMODE               => PDO::ERRMODE_EXCEPTION,
        PDO::ATTR_DEFAULT_FETCH_MODE    => PDO::FETCH_ASSOC,
    );
    public function __construct($dsn, $username, $password, $timeout = null){
        $this->dsn = $dsn;
        $this->username = $username;
        $this->password = $password;
        $this->timeout = intval($timeout);
        parent::__construct($dsn, $username, $password, $this->options);
        $this->exec("set names ".$this->charset);
    }
    public function execute($sql, $params = array()){
        $stmt = $this->prepare($sql);
        $execStatus=$stmt->execute($params);
        return $execStatus;
    }
    public function getAll($sql, $params = array()){
        $stmt = $this->prepare($sql);
        $stmt->execute($params);
        return $stmt->fetchAll();
    }
}
//对象适配器,使用委派
class ArticleModel{
    private $pdo=null;
    public function __construct($pdo){
        $this->pdo=$pdo;
    }
    //委派调用PDOAdapter的getAll方法
    public function getArticleList(){
        $res=$this->pdo->getAll("select * from countries");
        return $res;
    }
}
class Controller{
  public function doAction(){
      try {
          $pdo=new PDOAdapter("mysql:host=127.0.0.1;port=3306;dbname=phpfly","phpfly","phpfly");
          $model=new ArticleModel($pdo);
          $res=$model->getArticleList();
          var_dump($res);

      } catch (Exception $e) {
          var_dump($e->getMessage());
      }

  }
}
$c=new Controller();
$c->doAction();