(PHP 4, PHP 5) class_exists — 检查类是否已定义 bool class_exists ( string $class_name [, bool $autoload ] ) 如果由 class_name 所指的类已经定义,此函数返回 TRUE,否则返回 FALSE. Example #1 class_exists() 例子 <?php // Check the class exists before trying to use it if (class_exists(
class_exists — 检查类是否已定义 bool class_exists ( string $class_name [, bool $autoload = true ] ) 检查指定的类是否已定义. <?php class Person{ public $username; public $age; public $height; public $weight; public function __construct($usernam