PHP 單例模式程式碼片段

標籤：

 1 <?php 2  3 error_reporting(E_ALL | E_STRICT); 4  5 class single{ 6  7     public $hash; 8  9     static protected $ins = null;10 11     final protected function __construct(){ //final 能被繼承，不能被重寫（防止子類重寫構造方法）12         $this->hash = mt_rand(1,9999);13     }14 15     static public function getInstance(){16         if(self::$ins instanceof self){ //instanceof 判斷某個對象是不是某個類的執行個體17             return self::$ins;18         }19         self::$ins =  new self();20         return self::$ins;    21     }22 }23 24 $s1 = single::getInstance();25 $s2 = single::getInstance();26 27 var_dump($s1);28 var_dump($s2);29 30 //son類繼承single類31 class son extends single{32 }33 34 $s1 = son::getInstance();35 $s2 = son::getInstance();36 37 var_dump($s1);38 var_dump($s2);

頁面輸出

object(single)[1]  public ‘hash‘ => int 9762object(single)[1]  public ‘hash‘ => int 9762object(single)[1]  public ‘hash‘ => int 9762object(single)[1]  public ‘hash‘ => int 9762

 

PHP 單例模式程式碼片段