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关于单例模式的问题~

时间:2021-07-01 10:21:17 帮助过:9人阅读

  1. <!--?php/** * Created by PhpStorm. * User: Administrator * Date: 2015/8/30 * Time: 12:53 */class Singleton{ private static $instance = null; private function __construct($name){ $this--->name = $name; } public static function getInstance(){ if(self::$instance==null){ return new Singleton(""); } return self::$instance; } public function printString(){ echo "hello,this is printString()"."<br>"; } public function setName($name){ $this->name = $name; } public function getName(){ echo "The name is ".$this->name."<br>"; }}$class = Singleton::getInstance();$class->printString();$class->setName("jack");$class->getName();$class2 = Singleton::getInstance();$class2->getName();


为何 $class2->getName() 输出的 name 也为空呢?


回复讨论(解决方案)

return new Singleton(""):
应为
self::$instance = new Singleton(""):

如果 return new Singleton(""): 的话就直接返回了另一个实例
就不是单例模式了

  1. <!--?php/** * Created by PhpStorm. * User: Administrator * Date: 2015/8/30 * Time: 12:53 */class Singleton{ private static $instance = null; private function __construct($name){ $this--->name = $name; } public static function getInstance(){ if(self::$instance==null){ return new Singleton(""); } return self::$instance; } public function printString(){ echo "hello,this is printString()"."<br>"; } public function setName($name){ $this->name = $name; } public function getName(){ echo "The name is ".$this->name."<br>"; }}$class = Singleton::getInstance();$class->printString();$class->setName("jack");$class->getName();$class2 = Singleton::getInstance();$class2->getName();


为何 $class2->getName() 输出的 name 也为空呢?


谢谢楼上~

只要改一处代码即可:你忘了把单例放入$instance

  1. public static function getInstance(){ if(self::$instance==null){ self::$instance= new Singleton(""); } return self::$instance; }

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