singleton單例模式

class Db {   static private $_instance;   static private $_connectSource;   private $_dbConfig = array(      'host' => '127.0.0.1',      'user' => 'root',      'password' => '',      'database' => 'video',   );   private function __construct() {   }   static public function getInstance() {      if(!(self::$_instance instanceof self)) {         self::$_instance = new self();      }      return self::$_instance;   }   public function connect() {      if(!self::$_connectSource) {         self::$_connectSource = @mysql_connect($this->_dbConfig['host'], $this->_dbConfig['user'], $this->_dbConfig['password']);           if(!self::$_connectSource) {            throw new Exception('mysql connect error ' . mysql_error());            //die('mysql connect error' . mysql_error());}                  mysql_select_db($this->_dbConfig['database'], self::$_connectSource);         mysql_query("set names UTF8", self::$_connectSource);      }      return self::$_connectSource;   }}/*$connect = Db::getInstance()->connect();$sql = "select * from video";$result = mysql_query($sql, $connect);echo mysql_num_rows($result);
var_dump($result);*/

以上就介紹了 singleton單例模式，包括了方面的內容，希望對PHP教程有興趣的朋友有所協助。

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