在php中，__sleep和___wakeup是两个分别自对象序列化前和后分别调用的方法，
其中__sleep在一个对象序列化前调用，它不接收任何参数，但会返回数组，这里可以放置哪些属性需要序列化，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会序列化 }
}
$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属性会序列化，而creaditcard不会。
而__wakeup则相反，它是在反序列化前触发的，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”) {
//重新在数据库中获得
$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) ’1234567890123456³
}
上面的代码中，因为序列化时使用了__sleep,沒把creadit cardnumber属性序列化，因此在反序列化unserialize调用前，会先调用__wakeup方法，比如这里可以重新在数据库中取得数据，再此进行操作