我正在遵循数据映射器指南。但是它在mapper类中有一个模型类。所以我使用依赖注入对它进行了修改。
型号，
class User
{
/**
* @var int
*/
protected $userId;
/**
* @var string
*/
protected $username;
/**
* @var string
*/
protected $email;
/**
* @param null $id
* @param null $username
* @param null $email
*/
public function __construct($id = null, $username = null, $email = null)
{
$this->userId = $id;
$this->username = $username;
$this->email = $email;
}
/**
* @return int
*/
public function getUserId()
{
return $this->userId;
}
/**
* @param int $userId
*/
public function setUserID($userId)
{
$this->userId = $userId;
}
/**
* @return string
*/
public function getUsername()
{
return $this->username;
}
/**
* @param string $username
*/
public function setUsername($username)
{
$this->username = $username;
}
/**
* @return string
*/
public function getEmail()
{
return $this->email;
}
/**
* @param string $email
*/
public function setEmail($email)
{
$this->email = $email;
}
}
映射器，
class UserMapper
{
public function __construct($model)
{
$this->model = $model;
}
public function findAll()
{
$resultSet = array(
array('userid' => 1, 'username' => 'Odysseus', 'email' => 'Odysseus@ithaca.gr'),
array('userid' => 2, 'username' => 'Penelope', 'email' => 'Penelope@ithaca.gr')
);
$entries = array();
foreach ($resultSet as $row) {
$entries[] = $this->mapObject($row);
}
return $entries;
}
protected function mapObject(array $row)
{
$this->model->setUserID($row['userid']);
$this->model->setUsername($row['username']);
$this->model->setEmail($row['email']);
return $this->model;
}
}
用途，
$model = new User();
$mapper = new UserMapper($model);
$users = $mapper->findAll();
print_r($users);
结果（不正确），
Array
(
[0] => User Object
(
[userId:protected] => 2
[username:protected] => Penelope
[email:protected] => Penelope@ithaca.gr
)
[1] => User Object
(
[userId:protected] => 2
[username:protected] => Penelope
[email:protected] => Penelope@ithaca.gr
)
)
但它在没有依赖注入的情况下返回正确的结果，
protected function mapObject(array $row)
{
$entry = new User();
$entry->setUserID($row['userid']);
$entry->setUsername($row['username']);
$entry->setEmail($row['email']);
return $entry;
}
结果，
Array
(
[0] => User Object
(
[userId:protected] => 1
[username:protected] => Odysseus
[email:protected] => Odysseus@ithaca.gr
)
[1] => User Object
(
[userId:protected] => 2
[username:protected] => Penelope
[email:protected] => Penelope@ithaca.gr
)
)
那么，如何将依赖项注入与数据映射器一起使用以返回正确的结果呢？有什么想法吗？
编辑：
class UserMapper
{
protected function mapObject(array $row)
{
return new User($row['userid'], $row['username'], $row['email']);
}
}
不要这样做。唯一的解决方案是注入一个工厂，然后创建模型对象，但正如您在本主题的另一个问题中所解释的，这种额外的抽象级别在这里并不是真正必要的。数据映射程序本身负责创建对象。
这里有一个依赖注入的解决方案，您可以将对象创建委托给工厂。但我确信，你不会需要它。在大多数情况下，将数据映射器与其映射到的模型相耦合是合理的做法。
class UserMapper
{
public function __construct(UserFactory $userFactory)
{
$this->userFactory = $userFactory;
}
protected function mapObject(array $row)
{
return $userFactory->createUser($row['userid'], $row['username'], $row['email']);
}
}
interface UserFactory
{
public function createUser($id, $name, $email);
}
class DefaultUserFactory implements UserFactory
{
public function createUser($id, $name, $email)
{
return new User($id, $name, $email);
}
}