psr-4

自动加载：

 <?php

 function autoload($className)

 {

     $className = ltrim($className, '\\');

     $fileName  = '';

     $namespace = '';

     if ($lastNsPos = strrpos($className, '\\')) {

         $namespace = substr($className, 0, $lastNsPos);

         $className = substr($className, $lastNsPos + 1);

         $fileName  = str_replace('\\', DIRECTORY_SEPARATOR, $namespace) . DIRECTORY_SEPARATOR;

     }

     $fileName .= str_replace('_', DIRECTORY_SEPARATOR, $className) . '.php';

     require $fileName;

 }

 spl_autoload_register('autoload');