PHP Singleton mode example analysis, PHP singleton mode application Scenario

For an example of a singleton pattern in PHP design mode, the principles and Techniques of PHP singleton mode are used to learn the implementation of PHP singleton mode. Singleton mode (Duty mode): An object (before learning the design pattern, the need to understand the object-oriented thinking) is only responsible for a specific task; Singleton class: 1, the constructor needs to be marked as private (access control: Prevent external code from creating objects using the new operator), the Singleton class can not be instantiated in other classes, can only be instantiated by itself; 2. A static member variable 3 that holds an instance of the class, Have a public static method that accesses this instance (the common getinstance () method instantiates a singleton class, which can be detected by the instanceof operator whether the class has been instantiated)

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