原文地址

一. 问题

当我们 clone下来一个laravel框架，接着就开始我们表演，但是我们根据业务需求需要创建一些自定义的文件夹，那么我们该如何加载他们呢，如何避免这类错误[Symfony\\Component\\Debug\\Exception\\FatalThrowableError] Class 'tools\\alyduanxin\\api\_demo\\SmsDemo' not found

二：分三步来解决这个问题

• 在laravel 中项目根目录下创建自己的文件夹,例如我在项目根目录下创建了一个tools文件夹。

• 在项目文件夹的根目录下找到composer.json文件，在autoload里添加psr-4节点

  "psr-4": {
              "tools\\": "tools/"
          }

• 接着执行

  composer dump-autoload -o 

• 至此我们就加载成功啦

三. 解释一下 composer dump-autoload 这条命令

下面是composer官方文档中关于dump-autoload命令的解释：

dump-autoload

If you need to update the autoloader(类加载器) because of new classes in a classmap package for example, you can use “dump-autoload” to do that without having to go through an install or update.
Additionally, it can dump an optimized(优化) autoloader that converts(转化) PSR-0/4 packages into classmap ones for performance(性能) reasons. In large applications with many classes, the autoloader can take up a substantial portion of every request’s time. Using classmaps for everything is less convenient in development, but using this option you can still use PSR-0/4 for convenience and classmaps for performance.
Options:
--no-scripts: Skips the execution of all scripts defined in composer.json file.
--optimize (-o): Convert PSR-0/4 autoloading to classmap to get a faster autoloader. This is recommended especially for production, but can take a bit of time to run so it is currently not done by default.
--classmap-authoritative (-a): Autoload classes from the classmap only. Implicitly enables –optimize.
--apcu: Use APCu to cache found/not-found classes.
--no-dev: Disables autoload-dev rules.
其中官方推荐的参数是 -o,即 composer dump-autoload -o
这个命令可以将PSR-0/4自动加载成classmap来获取一个更快速的类加载器，推荐生产环境使用，但是，可能需要一点时间来运行，因此目前不是默认