我有一个映射到数据库行的用户类。我将其缓存在 memcached 中作为键值对，用户 id 作为 memcached 键。我想将所有用户功能封装到用户类中，包括填充用户类字段。从 PDO 获取时，我使用 PDO：：FETCH_INTO 将值存储在 self 对象中。如何使用内存缓存来做到这一点？
您的问题的措辞和后续评论有些模棱两可，但它们仍然为我指明了以下方向：
public function __construct($id) {
global $pdo, $memcached;
$data = $memcached->get($id);
if($memcached->getResultCode() == Memcached::RES_SUCCESS) {
// this is not currently allowed in PHP
$this = $data;
// this should be your fix
foreach($data AS $key => $value) {
$this->$key = $value;
}
// or this
foreach($this AS $key => $value) {
$this->$key = $data[$key];
}
// the difference between the fixes above is that
// the second is strictly limited to values defined
// by the class (current object)
}
else {
$pdos = $pdo->prepare('SELECT * FROM table_name WHERE id = ?');
if($pdos) {
// this is not allowed in PHP
$pdos->execute(array(intval($id)));
$this = $pdos->fetch(PDO::FETCH_CLASS, get_class($this));
// all of this should work fine and is allowed
$pdos->setFetchMode(PDO::FETCH_INTO, $this);
$pdos->execute(array(intval($id)));
$pdos->fetch(PDO::FETCH_INTO);
}
}
}
但不幸的是，PHP 不允许在内部（在其自己的方法调用中）覆盖 $this 的值，因此作为替代方案可以做的是使用静态方法。
public static function getByID($id) {
global $pdo, $memcached;
$data = $memcached->get($id);
if($memcached->getResultCode() == Memcached::RES_SUCCESS) {
// this will work if your objects construct has a
// foreach similar to the ones presented above
$result = new self($data);
// or if you don't want to write a foreach in
// the construct you can have it here
foreach($data AS $key => $value) {
$this->$key = $value;
}
// or here
foreach($this AS $key => $value) {
$this->$key = $data[$key];
}
}
else {
$pdos = $pdo->prepare('SELECT * FROM table_name WHERE id = ?');
if($pdos) {
// either of these should work
$pdos->execute(array(intval($id)));
$result = $pdos->fetch(PDO::FETCH_CLASS, get_class($this));
// either of these should work
$result = new self;
$pdos->setFetchMode(PDO::FETCH_INTO, $result);
$pdos->execute(array(intval($id)));
$pdos->fetch(PDO::FETCH_INTO);
}
}
return($result);
}
用法语法将MyClass::get($some_id) 。
答案要么是"只是做"，要么是"你不做"。
如果您将信息单独保存为键/值，则不能只通过一次点击来完成，只需手动检索它们（创建一个新对象，用 memcached 中的计算键填充自身）。
如果你有一个对象在memcached中序列化，你可以检索它并反序列化。