rails无法加载此类文件 – mysql2 / mysql2（LoadError）
我是ruby on rails的新手我无法找到此错误的解决方案：
rails s /usr/local/share/gems/gems/mysql2-0.3.13/lib/mysql2.rb:8:in `require': cannot load such file -- mysql2/mysql2 (LoadError) from /usr/local/share/gems/gems/mysql2-0.3.13/lib/mysql2.rb:8:in `' from /usr/local/share/gems/gems/bundler-1.3.5/lib/bundler/runtime.rb:72:in `require' from /usr/local/share/gems/gems/bundler-1.3.5/lib/bundler/runtime.rb:72:in `block (2 levels) in require' from /usr/local/share/gems/gems/bundler-1.3.5/lib/bundler/runtime.rb:70:in `each' from /usr/local/share/gems/gems/bundler-1.3.5/lib/bundler/runtime.rb:70:in `block in require' from /usr/local/share/gems/gems/bundler-1.3.5/lib/bundler/runtime.rb:59:in `each' from /usr/local/share/gems/gems/bundler-1.3.5/lib/bundler/runtime.rb:59:in `require' from /usr/local/share/gems/gems/bundler-1.3.5/lib/bundler.rb:132:in `require' from /home/Harish/Documents/simple_cms/config/application.rb:7:in `' from /usr/local/share/gems/gems/railties-4.0.0/lib/rails/commands.rb:76:in `require' from /usr/local/share/gems/gems/railties-4.0.0/lib/rails/commands.rb:76:in `block in ' from /usr/local/share/gems/gems/railties-4.0.0/lib/rails/commands.rb:73:in `tap' from /usr/local/share/gems/gems/railties-4.0.0/lib/rails/commands.rb:73:in `' from bin/rails:4:in `require' from bin/rails:4:in `'
gem uninstall mysql2 gem install mysql2 --platform=ruby
删除rails特定包目录中的mysql2 gem目录并复制粘贴这个新安装的mysql2 gem
对于Rails 3.2.17和Ruby 1.9.3-p448以及mysql2 0.3.11，运行bundle update mysql2更新到0.3.15并为我摆脱了错误。
Ya，这与mysql2 gem的新版本（0.3.13）和rails 4.0.0一起发生。 删除供应商目录下的捆绑文件夹，并重新运行捆绑安装，更新为我解决了这个问题
cd {Your_RailsApp_Root}/vendor/ rm -rf bundle/ cd {Your_RailsApp_Root} bundle install bundle update
你有安装mysql2 gem吗？ 检查你的gemfile是否有gem "mysql2" ，然后从rails应用程序的根目录运行bundle install 。 另外，确保在开发环境中下载了mysql。
只是降级mysql2版本。 在我的情况下，我使用’0.2.6’版本，它适用于我。
gem 'mysql2', '0.2.6'
使用ruby版本2.0.0和gem版本1.8.25
这解决了我的错误：
[root @ localhost cms] #su Harish
[Harish @ localhost cms] $ bundle install
[Harish @ localhost cms] $ rails s