Describes the cause and action for error messages.
Error Message(English)：
class excel does not exist lumen
Class excel does not exist in Laravel 5.2 - Stack Overflow
https://stackoverflow.com/questions/41088071/class-excel-does-not-exist-in-laravel-5-2
Lumen : maatwebsite/excel is not working properly
https://stackoverflow.com/questions/50392047/lumen-maatwebsite-excel-is-not-working-properly
Laravel - Call to undefined method Maatwebsite\Excel\Excel ...
https://stackoverflow.com/questions/49401151/laravel-call-to-undefined-method-maatwebsite-excel-exce・・・
Lumen 5.3: 'Class filesystem does not exist' in /var/www ...
https://stackoverflow.com/questions/44732246/lumen-5-3-class-filesystem-does-not-exist-in-var-www-pr・・・
Class 'App\Http\Controllers\Excel' not found in Laravel
https://stackoverflow.com/questions/30155145/class-app-http-controllers-excel-not-found-in-laravel
Laravelでroute:listやろうとしたらReflectionExceptionが出た原因 | なか ...
https://blog.nakachon.com/2017/05/29/the-reason-for-reflection-exception-error/
(1/1) FatalErrorException Class 'Excel' not found in MastersController ...
https://laracasts.com/discuss/channels/laravel/11-fatalerrorexception-class-excel-not-found-in-maste・・・
Lumen の Controller の namespace について - takaya030の備忘録
http://takaya030.hatenablog.com/entry/2016/06/25/223734
Supercharge your Excel exports in Laravel! ? Maatwebsite ? Medium
https://medium.com/maatwebsite/supercharge-your-excel-exports-in-laravel-eb9f74395995