单例/单态模式(Singleton Pattern)

百度词条的解释

http://baike.baidu.com/view/1859857.htm

<?php//单例模式final class PSV {private $loan = false;private static $myPSV;public function getInstance() {if(!isset(self::$myPSV)) {self::$myPSV = new PSV();}return self::$myPSV;}public function setLoan() {$this->loan = !$this->loan;}public function getLoan() {return $this->loan;}//禁止外部new或者clone对象private function __construct() {}private function __clone() {}}$myPSV = PSV::getInstance();var_dump($myPSV->getLoan());$myPSV->setLoan();var_dump($myPSV->getLoan());?>

//单态模式class PSV {private static $loan = false;public function setLoan() {self::$loan = !self::$loan;}public function getLoan() {return self::$loan;}}$myPSV = new PSV();var_dump($myPSV->getLoan());$myFriendPSV = new PSV();$myFriendPSV->setLoan();var_dump($myPSV->getLoan());