php判断类是否存在函数class_exists

bool class_exists ( string $class_name [, bool $autoload = true ] )

此功能是否给定的类被定义检查,返回true,如果class_name是一个定义的类,否则返回false.

php实例代码如下:

if (class_exists('myclass')) {

$myclass = new myclass();

}

function __autoload($class)

{

include($class . '.php');

// check to see whether the include declared the class

if (!class_exists($class, false)) {

trigger_error("unable to load class: $class", e_user_warning);

}

}

if (class_exists('myclass')) {

$myclass = new myclass();

}//开源代码phpfensi.com