是否可以在PHP中创建静态类（如C＃中）？ [英] Is it possible to create static classes in PHP (like in C#)?

问题描述

我想在PHP中创建一个静态类，它的行为就像在C＃中一样，所以

1. 构造函数被自动调用对课程的第一次电话


2. 不需要实例化

这样的东西...

  static class Hello {
 private static $ greeting ='Hello' 
 
 private __construct（）{
 $ greeting。='There！'; 
} 
 
 public static greet（）{
 echo $ greeting; 
} 
} 
 
 Hello :: greet（）; // 你好！ 
  

解决方案

您可以在PHP中安装静态类， t自动调用构造函数（如果您尝试调用 self :: __ construct（），您将收到错误。）

因此，您必须创建一个 initialize（）函数并在每个方法中调用它：

 <？php 
 
 class Hello 
 {
 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（）; // 你好！ 
 
 
？> 
  

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

1. Constructor is automatically called on the first call to the class
2. 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!

解决方案

You can have static classes in PHP but they don't call the constructor automatically (if you try and call self::__construct() you'll get an error).

Therefore you'd have to create an initialize() function and call it in each method:

<?php

class Hello
{
    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!


?>

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