PHP 的单例模式代码

1. class User {
2. static function getInstance()
3. {
4. if (self::$instance == NULL) { // If instance is not created yet, will create it.
5. self::$instance = new User();
6. }
7. return self::$instance;
8. }
9. private function __construct()
10. // Constructor method as private so by mistake developer not crate
11. // second object of the User class with the use of new operator
12. {
13. }
14. private function __clone()
15. // Clone method as private so by mistake developer not crate
16. //second object of the User class with the use of clone.
17. {
18. }
20. function Log($str)
21. {
22. echo $str;
23. }
24. static private $instance = NULL;
25. }
26. User::getInstance()->Log("Welcome User");

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PHP