php中_sleep跟_wakeup

php中__sleep和__wakeup
在php中，__sleep和___wakeup是兩個分別自對象序列化前和後分別調用的方法，
其中__sleep在一個對象序列化前調用，它不接收任何參數，但會返回數組，這裡可以放置哪些屬性需要序列化，比如下面的例子：

class Customer { private $name; private $credit_card_number;  public function setName($name) { $this->name = $name; } public function getName() { return $this->name; } public function setCC($cc) { $this->credit_card_number = $cc; } public function getCC() { return $this->credit_card_number; } public function __sleep() { return array(“name”); //只有name會序列化 } } $c = new Customer(); $c->setName(“Stuard”); $c->setCC(“456789″); $data = serialize($c).”\n”; echo $data.”\n”; Output: O:8:”Customer”:1:{s:14:” Customer name”;s:5:”Stuard”;}

上面在序列化前，__sleep中指定了只有name屬性會序列化，而creaditcard不會。

而__wakeup則相反，它是在還原序列化前觸發的，比如下面例子：

class Customer { private $name; private $credit_card_number;  public function setName($name) { $this->name = $name; } public function getName() { return $this->name; } public function setCC($cc) { $this->credit_card_number = $cc; } public function getCC() { return $this->credit_card_number; } public function __sleep() { return array(“name”); } public function __wakeup() { if($this->name == “Stuart”) {  //重新在資料庫中獲得  $this->credit_card_number = “1234567890123456″; } } } $c = new Customer(); $c->setName(“Stuart”); $c->setCC(“1234567890123456″); $data = serialize($c).”\n”; var_dump(unserialize($data)); Output: object(Customer)#2 (2) { ["?name:private"?]=> string(5) “Stuart”? ["?credit_card_number:private"]=> string(16) ’1234567890123456? }

上面的代碼中，因為序列化時使用了__sleep,沒把creadit cardnumber屬性序列化，因此在還原序列化unserialize調用前，會先調用__wakeup方法，比如這裡可以重新在資料庫中取得資料，再此進行操作

