是否可以在PHP中创建静态类（像C#中一样）？

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问题描述

我想在PHP中创建一个静态类，并像在C#中一样行事，所以

构造函数会自动在第一个呼叫中呼叫
无需实例化

这种东西...

static class Hello {
    private static $greeting = 'Hello';

    private __construct() {
        $greeting .= ' There!';
    }

    public static greet(){
        echo $greeting;
    }
}

Hello::greet(); // Hello There!

其他推荐答案

除了格雷格的答案外，我还建议将构造函数设置为私有，以便不可能实例化课程.

因此，以我的拙见，这是一个基于格雷格的示例:

<?php

class Hello
{
    /**
     * Construct won't be called inside this class and is uncallable from
     * the outside. This prevents instantiating this class.
     * This is by purpose, because we want a static class.
     */
    private function __construct() {}
    private static $greeting = 'Hello';
    private static $initialized = false;

    private static function initialize()
    {
        if (self::$initialized)
            return;

        self::$greeting .= ' There!';
        self::$initialized = true;
    }

    public static function greet()
    {
        self::initialize();
        echo self::$greeting;
    }
}

Hello::greet(); // Hello There!


?>

其他推荐答案

您可以拥有类似"静态"的类.但是我想，确实缺少一些重要的东西:在PHP中，您没有应用程序周期，因此您在整个应用程序中都不会获得真正的静态(或单身)...

请参阅 php

中的单身人士

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问题描述

I want to create a static class in PHP and have it behave like it does in C#, so

Constructor is automatically called on the first call to the class
No instantiation required

Something of this sort...

static class Hello {
    private static $greeting = 'Hello';

    private __construct() {
        $greeting .= ' There!';
    }

    public static greet(){
        echo $greeting;
    }
}

Hello::greet(); // Hello There!

其他推荐答案

In addition to Greg's answer, I would recommend to set the constructor private so that it is impossible to instantiate the class.

So in my humble opinion this is a more complete example based on Greg's one:

<?php

class Hello
{
    /**
     * Construct won't be called inside this class and is uncallable from
     * the outside. This prevents instantiating this class.
     * This is by purpose, because we want a static class.
     */
    private function __construct() {}
    private static $greeting = 'Hello';
    private static $initialized = false;

    private static function initialize()
    {
        if (self::$initialized)
            return;

        self::$greeting .= ' There!';
        self::$initialized = true;
    }

    public static function greet()
    {
        self::initialize();
        echo self::$greeting;
    }
}

Hello::greet(); // Hello There!


?>

其他推荐答案

you can have those "static"-like classes. but i suppose, that something really important is missing: in php you don't have an app-cycle, so you won't get a real static (or singleton) in your whole application...

see Singleton in PHP

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