php 类常量调用 $this::CONST

php class constant call $this::CONST

本文关键字：this CONST 调用常量 php | 更新日期: 2023-09-27

为什么我可以从动态声明调用类常量？这段代码效果很好：

echo $this::CONST;

来自 http://php.net/manual/en/language.oop5.constants.php

<?php
class MyClass
{
    const CONSTANT = 'constant value';
    function showConstant() {
        echo  self::CONSTANT . "'n";
    }
}
echo MyClass::CONSTANT . "'n";
$classname = "MyClass";
echo $classname::CONSTANT . "'n"; // As of PHP 5.3.0
$class = new MyClass();
$class->showConstant();
echo $class::CONSTANT."'n"; // As of PHP 5.3.0
?>