Ruby on Rails-无法加载此类文件-mysql2 / 2.2 / mysql2（LoadError）

Hassan Yousuf 发表于 Dev

哈桑·优素福（Hassan Yousuf）

我在Rails项目中使用的是SQLite，但是当听说Heroku不支持SQLite时，我改用了MYSQL。

切换数据库后，我启动了rails服务器“ rails s”，但它给了我以下错误：

    C:\Sites\simple_cms>rails server
C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/mysql2-0.3.18-x64-mingw32/lib/mysql2/mysql2.rb:2:in `require'
: cannot load such file -- mysql2/2.2/mysql2 (LoadError)
        from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/mysql2-0.3.18-x64-mingw32/lib/mysql2/mysql2.rb:2
:in `<top (required)>'
        from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/mysql2-0.3.18-x64-mingw32/lib/mysql2.rb:31:in `r
equire'
        from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/mysql2-0.3.18-x64-mingw32/lib/mysql2.rb:31:in `<
top (required)>'
        from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/bundler-1.8.4/lib/bundler/runtime.rb:76:in `requ
ire'
        from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/bundler-1.8.4/lib/bundler/runtime.rb:76:in `bloc
k (2 levels) in require'
        from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/bundler-1.8.4/lib/bundler/runtime.rb:72:in `each
'
        from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/bundler-1.8.4/lib/bundler/runtime.rb:72:in `bloc
k in require'
        from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/bundler-1.8.4/lib/bundler/runtime.rb:61:in `each
'
        from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/bundler-1.8.4/lib/bundler/runtime.rb:61:in `requ
ire'
        from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/bundler-1.8.4/lib/bundler.rb:134:in `require'
        from C:/Sites/simple_cms/config/application.rb:7:in `<top (required)>'
        from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/railties-4.2.0/lib/rails/commands/commands_tasks
.rb:78:in `require'
        from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/railties-4.2.0/lib/rails/commands/commands_tasks
.rb:78:in `block in server'
        from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/railties-4.2.0/lib/rails/commands/commands_tasks
.rb:75:in `tap'
        from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/railties-4.2.0/lib/rails/commands/commands_tasks
.rb:75:in `server'
        from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/railties-4.2.0/lib/rails/commands/commands_tasks
.rb:39:in `run_command!'
        from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/railties-4.2.0/lib/rails/commands.rb:17:in `<top
 (required)>'
        from bin/rails:4:in `require'
        from bin/rails:4:in `<main>'

这是我的gemfile：

# Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
gem 'rails', '4.2.0'
# Use mysql as the database for Active Record
gem 'mysql2'

我进行了彻底搜索，找到了一些答案，但是没有用。

我将libmysql.dll档案从粘贴Program Files/MySQL Server 5.6到，Ruby/bin但还是没有运气。我执行了以下命令：

gem uninstall mysql2

gem install mysql2 --platform=ruby

我遵循了本教程，仍然遇到相同的错误：错误“ ...无法加载此类文件-mysql2 / 2.0 / mysql2（LoadError）”。在装有Ruby 2.0.0的Windows XP上

如果有人能帮助我，我将非常感激，以便我可以将其部署到Heroku。

谢谢。

理查德·派克

问题是mysql2gem没有以其本机依赖项安装。在以前的Ruby版本中，这将触发unable to build native gem extension错误：

在此处输入图片说明

发生了一些变化，Ruby 2.2因此您可以安装gem而不用构建本机扩展。但是，这并不意味着问题已得到解决-因此您必须确保以适当的依赖项安装gem。

教程：

从MYSQL下载C连接器（请注意您的Ruby版本-如果您使用的是64位，请下载64位版本）
将MYSQL C-Connector文件夹解压缩/安装到HDD上（路径中没有空格）
运行以下命令： gem install mysql2 --platform=ruby -- '--with-mysql-dir="C:/your-mysql-connector-path"'
这应该将gem与所需的文件一起安装
然后，您可以libmysql.dll从C:/your-mysql-connector-path-> c：/ your-ruby-install / bin`复制