PHP 7 介绍了过滤 unserialize() 函数在对不可信数据进行反序列化时提供更好的安全性。它可以防止可能的代码注入，并使开发人员能够将可以非序列化的类列入白名单。
<?php
class MyClass1 {
public $obj1prop;
}
class MyClass2 {
public $obj2prop;
}
$obj1 = new MyClass1();
$obj1->obj1prop = 1;
$obj2 = new MyClass2();
$obj2->obj2prop = 2;
$serializedObj1 = serialize($obj1);
$serializedObj2 = serialize($obj2);
// default behaviour that accepts all classes
// second argument can be ommited.
// if allowed_classes is passed as false, unserialize converts all objects into __PHP_Incomplete_Class object
$data = unserialize($serializedObj1 , ["allowed_classes" => true]);
// converts all objects into __PHP_Incomplete_Class object except those of MyClass1 and MyClass2
$data2 = unserialize($serializedObj2 , ["allowed_classes" => ["MyClass1", "MyClass2"]]);
print($data->obj1prop);
print("<br/>");
print($data2->obj2prop);
?>它产生以下浏览器输出–
1
2