1.composer install出现的问题：
Problem 1
- Installation request for phpoffice/phpexcel 1.8.1 -> satisfiable by phpoffice/phpexcel[1.8.1].
- phpoffice/phpexcel 1.8.1 requires ext-xmlwriter * -> the requested PHP extension xmlwriter is missing from your system.
此时用yum install php-xmlwriter(linux-centos)
Problem 2
- danielstjules/stringy 1.10.0 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
- danielstjules/stringy 1.10.0 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
- Installation request for danielstjules/stringy 1.10.0 -> satisfiable by danielstjules/stringy[1.10.0].
此时用yum install php56w-mbstring(linux-centos)
2.php artisan clear-compiled
[BadMethodCallException]
Method auth does not exist.
出现这个错误的解决方案：