What is the php Singleton mode?

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Static function getInstance ($ class, $ param = array () {if (! Isset ($ obj [$ class]) {$ obj [$ class] = new $ class ($ param);} return $ obj [$ class];} when instantiating a class, first determine whether there is an instance of this class. if there is one, it will not be instantiated. Otherwise, it will be instantiated.

Amazing! Talk is cheap, show you my code.

The simplest PHP Singleton mode class:

Class TestInstance {public static $ _ instance = null; // The constructor uses protected to prevent external new classes. this is the key to the Singleton mode. protected function _ Construct () {echo 'instance, Instance, Instance .......... ';} // an instance that uses a static variable storage class. it is assigned only when it is instantiated for the first time. in the future, the public static function getInstance () {if (! Isset (self ::$ _ instance) {self ::$ _ instance = new static ();} return self ::$ _ instance ;}}