(No version information available, might only be in SVN)
自定义序列化的接口。
实现此接口的类将不再支持 __sleep() 和 __wakeup()。不论何时，只要有实例需要被序列化，serialize 方法都将被调用。它将不会调用 __destruct() 或有其他影响，除非程序化地调用此方法。当数据被反序列化时，类将被感知并且调用合适的 unserialize() 方法而不是调用 __construct()。如果需要执行标准的构造器，你应该在这个方法中进行处理。
Example #1 Basic usage
<?php
class obj implements Serializable {
private $data;
public function __construct() {
$this->data = "My private data";
}
public function serialize() {
return serialize($this->data);
}
public function unserialize($data) {
$this->data = unserialize($data);
}
public function getData() {
return $this->data;
}
}
$obj = new obj;
$ser = serialize($obj);
$newobj = unserialize($ser);
var_dump($newobj->getData());
?>
以上例程的输出类似于：
string(15) "My private data"
marcos dot gottardi at folha dot REM0VE-THIS dot com dot br (2012-01-13 09:05:09)
Serializing child and parent classes:
<?php
class MyClass implements Serializable {
private $data;
public function __construct($data) {
$this->data = $data;
}
public function getData() {
return $this->data;
}
public function serialize() {
echo "Serializing MyClass...\n";
return serialize($this->data);
}
public function unserialize($data) {
echo "Unserializing MyClass...\n";
$this->data = unserialize($data);
}
}
class MyChildClass extends MyClass {
private $id;
private $name;
public function __construct($id, $name, $data) {
parent::__construct($data);
$this->id = $id;
$this->name = $name;
}
public function serialize() {
echo "Serializing MyChildClass...\n";
return serialize(
array(
'id' => $this->id,
'name' => $this->name,
'parentData' => parent::serialize()
)
);
}
public function unserialize($data) {
echo "Unserializing MyChildClass...\n";
$data = unserialize($data);
$this->id = $data['id'];
$this->name = $data['name'];
parent::unserialize($data['parentData']);
}
public function getId() {
return $this->id;
}
public function getName() {
return $this->name;
}
}
$obj = new MyChildClass(15, 'My class name', 'My data');
$serial = serialize($obj);
$newObject = unserialize($serial);
echo $newObject->getId() . PHP_EOL;
echo $newObject->getName() . PHP_EOL;
echo $newObject->getData() . PHP_EOL;
?>
This will output:
Serializing MyChildClass...
Serializing MyClass...
Unserializing MyChildClass...
Unserializing MyClass...
15
My class name
My data
Anonymous (2011-07-05 07:01:02)
You cannot throw an exception inside the serialize() method. This will cause PHP to complain that you are not returning a string or NULL.
The best way to prevent the serialization of an object is to throw an Exception in the __sleep() method:
<?php
class Obj {
public function __sleep() {
throw new BadMethodCallException('You cannot serialize this object.');
}
}
?>
Anonymous (2011-05-12 06:09:23)
You can prevent an object getting unserialized by returning NULL. Instead of a serialized object, PHP will return the serialized form of NULL:
<?php
class testNull implements Serializable {
public function serialize() {
return NULL;
}
public function unserialize($data) {
}
}
$obj = new testNull;
$string = serialize($obj);
echo $string; // "N;"
?>
That's perhaps better than throwing exceptions inside of the serialize function if you want to prevent serialization of certain objects.