Home Backend Development PHP Tutorial Detailed explanation of PHP singleton mode demo

Detailed explanation of PHP singleton mode demo

Feb 24, 2018 pm 02:32 PM
demo php Detailed explanation

This article mainly shares with you the singleton mode demo of PHP design pattern, hoping to help everyone learn the PHP singleton mode better.

<?php/** 
* 设计模式之单例模式
 * $_instance必须声明为静态的私有变量
 * 构造函数和析构函数必须声明为私有,防止外部程序new
 * 类从而失去单例模式的意义
 * getInstance()方法必须设置为公有的,必须调用此方法
 * 以返回实例的一个引用
 * ::操作符只能访问静态变量和静态函数
 * new对象都会消耗内存
 * 使用场景:最常用的地方是数据库连接。
 * 使用单例模式生成一个对象后,
 * 该对象可以被其它众多对象所使用。
 */class Example{//保存例实例在此属性中
    private static $_instance;//构造函数声明为private,防止直接创建对象
    public function __construct()
    {
        //初始的方法
    }//单例方法
    public static function getInstance()
    {
        if(!isset(self::$_instance))
        {            $c=__CLASS__;            self::$_instance=new $c;
        }        return self::$_instance;
    }    function test()
    {
        echo("test");
    }
}// 这个写法会出错,因为构造方法被声明为private//$test = new Example;// 下面将得到Example类的单例对象$test = Example::getInstance();$test->test();?>
<?php/**
 * 设计模式之单例模式
 * $_instance必须声明为静态的私有变量
 * 构造函数和析构函数必须声明为私有,防止外部程序new
 * 类从而失去单例模式的意义
 * getInstance()方法必须设置为公有的,必须调用此方法
 * 以返回实例的一个引用
 * ::操作符只能访问静态变量和静态函数
 * new对象都会消耗内存
 * 使用场景:最常用的地方是数据库连接。
 * 使用单例模式生成一个对象后,
 * 该对象可以被其它众多对象所使用。
 */class Example{//保存例实例在此属性中
    private static $_instance;//构造函数声明为private,防止直接创建对象
    public function __construct()
    {
        //初始的方法
    }//单例方法
    public static function getInstance()
    {
        if(!isset(self::$_instance))
        {            $c=__CLASS__;            self::$_instance=new $c;
        }        return self::$_instance;
    }    function test()
    {
        echo("test");
    }
}// 这个写法会出错,因为构造方法被声明为private//$test = new Example;// 下面将得到Example类的单例对象$test = Example::getInstance();$test->test();?>

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Simple usage sharing of PHP singleton mode

php singleton mode example analysis

What is PHP singleton pattern? Detailed explanation of singleton mode usage

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