Analyse d'exemples de sérialisation et de désérialisation PHP

<?php
class Person {
  var $name;
  var $sex;
  var $age;
  function __construct($name = "", $sex = "男", $age = 22) {
    $this->name = $name;
    $this->sex = $sex;
    $this->age = $age;
  }
  function say() {
    echo $this->name . "在说话<br/>";
  }
  function run() {
    echo "在走路·<br/>";
  }
  //串行化的时候自动调用，成员$sex被忽略，只串行$name,$age
  function __sleep() {
    $arr = array("name","age");
    return $arr;
  }
  //反串行化时自动调用
  function __wakeup() {
    $this->age = 33;
  }
}
class Student extends Person {
  var $school;
  function __construct($name = "", $sex = "男", $age = 22,$school="") {
    parent::__construct($name,$sex,$age);
    $this->school = $school;
  }
  function study() {
    echo $this->name."正在".$this->school."学习<br/>";
  }
}
class Teacher extends Student {
  var $wage;
  function teaching() {
    echo $this->name."正在".$this->school."教学，每月工资为".$this->wage."<br/>";
  }
  //如果调用了不存在的方法，将会自动调用__call()，不会报错
  function __call($functionName,$args) {
    echo "函数名：".$functionName;
    print_r($args);
    echo "<br/>";
  }
}
$teacher1 = new Teacher("kaifu","男",22);
$teacher1->school = "edu";
$teacher1->wage = 4000;
$teacher1->say();
$teacher1->study();
$teacher1->teaching();
$teacher1->hello(1,2,3);
?>

<?php
  require_once &#39;Person.php&#39;;
  $teacher = new Teacher("tom","男",22);
  $teacher_str = serialize($teacher);
  file_put_contents("file.txt", $teacher_str);
  //反串行化
  $objStr = file_get_contents("file.txt");
  $t = unserialize($objStr);
  echo $t->age;
?>

O:7:"Teacher":2:{s:4:"name";s:3:"tom";s:3:"age";i:22;}