php serialize()與unserialize() 不完全研究

?php
//聲明一個(gè)類
class dog {

  var $name;
  var $age;
  var $owner;

  function dog($in_name="unnamed",$in_age="0",$in_owner="unknown") {
    $this->name = $in_name;
    $this->age = $in_age;
    $this->owner = $in_owner;
  }

  function getage() {
    return ($this->age * 365);
  }
  
  function getowner() {
    return ($this->owner);
  }
  
  function getname() {
    return ($this->name);
  }
}
//實(shí)例化這個(gè)類
$ourfirstdog = new dog("Rover",12,"Lisa and Graham");
//用serialize函數(shù)將這個(gè)實(shí)例轉(zhuǎn)化為一個(gè)序列化的字符串
$dogdisc = serialize($ourfirstdog);
print $dogdisc; //$ourfirstdog 已經(jīng)序列化為字符串 O:3:"dog":3:{s:4:"name";s:5:"Rover";s:3:"age";i:12;s:5:"owner";s:15:"Lisa and Graham";}

print 'BR>';

/* 
-----------------------------------------------------------------------
  在這里你可以將字符串 $dogdisc 存儲(chǔ)到任何地方如 session,cookie,數(shù)據(jù)庫(kù),php文件 
-----------------------------------------------------------------------
*/

//我們?cè)诖俗N這個(gè)類
unset($ourfirstdog);

/*  還原操作  */

/* 
-----------------------------------------------------------------------
  在這里將字符串 $dogdisc 從你存儲(chǔ)的地方讀出來如 session,cookie,數(shù)據(jù)庫(kù),php文件 
-----------------------------------------------------------------------
*/


//我們?cè)谶@里用 unserialize() 還原已經(jīng)序列化的對(duì)象
$pet = unserialize($dogdisc); //此時(shí)的 $pet 已經(jīng)是前面的 $ourfirstdog 對(duì)象了
//獲得年齡和名字屬性
$old = $pet->getage();
$name = $pet->getname();
//這個(gè)類此時(shí)無需實(shí)例化可以繼續(xù)使用,而且屬性和值都是保持在序列化之前的狀態(tài)
print "Our first dog is called $name and is $old days oldbr>";
print 'BR>';
?>