2017年如何做到这一点:

spl_autoload_register( function ($class_name) {
    $CLASSES_DIR = __DIR__ . DIRECTORY_SEPARATOR . 'classes' . DIRECTORY_SEPARATOR;  // or whatever your directory is
    $file = $CLASSES_DIR . $class_name . '.php';
    if( file_exists( $file ) ) include $file;  // only include if file exists, otherwise we might enter some conflicts with other pieces of code which are also using the spl_autoload_register function
} );

这里由PHP文档推荐:自动加载类

这只是卡斯顿代码的修改

function include_all_php($folder){
    foreach (glob("{$folder}/*.php") as $filename)
    {
        include $filename;
    }
}

include_all_php("my_classes");

不要编写函数()在目录中包含文件。你可能会失去变量作用域，可能不得不使用“global”。只需循环文件。

另外，当一个包含的文件的类名将扩展到另一个文件中定义的另一个类时，您可能会遇到困难——这个文件还没有包含。所以，要小心。

如果你想包含所有在一个目录和它的子目录:

$dir = "classes/";
$dh  = opendir($dir);
$dir_list = array($dir);
while (false !== ($filename = readdir($dh))) {
    if($filename!="."&&$filename!=".."&&is_dir($dir.$filename))
        array_push($dir_list, $dir.$filename."/");
}
foreach ($dir_list as $dir) {
    foreach (glob($dir."*.php") as $filename)
        require_once $filename;
}

不要忘记，它将使用字母顺序来包括您的文件。

你可以使用set_include_path:

set_include_path('classes/');

http://php.net/manual/en/function.set-include-path.php

2017年如何做到这一点:

spl_autoload_register( function ($class_name) {
    $CLASSES_DIR = __DIR__ . DIRECTORY_SEPARATOR . 'classes' . DIRECTORY_SEPARATOR;  // or whatever your directory is
    $file = $CLASSES_DIR . $class_name . '.php';
    if( file_exists( $file ) ) include $file;  // only include if file exists, otherwise we might enter some conflicts with other pieces of code which are also using the spl_autoload_register function
} );

这里由PHP文档推荐:自动加载类