composer

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)

composer

原文：http://www.cnblogs.com/Aaronqcd/p/5281728.html