`require': 无法加载这样的文件 -- mysql2/mysql2答案

【问题标题】：`require': cannot load such file -- mysql2/mysql2`require': 无法加载这样的文件 -- mysql2/mysql2
【发布时间】：2019-06-14 15:50:30
【问题描述】：

在遇到困难但使用成功安装mysql2 v 0.4.2之后

gem install mysql2 -v '0.4.2' -- --srcdir=/usr/local/mysql/include

我现在在运行bundle exec rails s时遇到以下错误

`require': cannot load such file -- mysql2/mysql2 (LoadError)
    from /Users/jmayer/.rvm/gems/ruby-2.3.1/gems/mysql2-0.4.2/lib/mysql2.rb:31:in `<top (required)>'
    from /Users/jmayer/.rvm/gems/ruby-2.3.1/gems/bundler-1.15.4/lib/bundler/runtime.rb:82:in `require'
    from /Users/jmayer/.rvm/gems/ruby-2.3.1/gems/bundler-1.15.4/lib/bundler/runtime.rb:82:in `block (2 levels) in require'
    from /Users/jmayer/.rvm/gems/ruby-2.3.1/gems/bundler-1.15.4/lib/bundler/runtime.rb:77:in `each'
    from /Users/jmayer/.rvm/gems/ruby-2.3.1/gems/bundler-1.15.4/lib/bundler/runtime.rb:77:in `block in require'
    from /Users/jmayer/.rvm/gems/ruby-2.3.1/gems/bundler-1.15.4/lib/bundler/runtime.rb:66:in `each'
    from /Users/jmayer/.rvm/gems/ruby-2.3.1/gems/bundler-1.15.4/lib/bundler/runtime.rb:66:in `require'
    from /Users/jmayer/.rvm/gems/ruby-2.3.1/gems/bundler-1.15.4/lib/bundler.rb:108:in `require'
    from /Users/jmayer/workspace/sekai-property/config/application.rb:8:in `<top (required)>'
    from /Users/jmayer/.rvm/gems/ruby-2.3.1/gems/railties-4.2.5/lib/rails/commands/commands_tasks.rb:78:in `require'
    from /Users/jmayer/.rvm/gems/ruby-2.3.1/gems/railties-4.2.5/lib/rails/commands/commands_tasks.rb:78:in `block in server'
    from /Users/jmayer/.rvm/gems/ruby-2.3.1/gems/railties-4.2.5/lib/rails/commands/commands_tasks.rb:75:in `tap'
    from /Users/jmayer/.rvm/gems/ruby-2.3.1/gems/railties-4.2.5/lib/rails/commands/commands_tasks.rb:75:in `server'
    from /Users/jmayer/.rvm/gems/ruby-2.3.1/gems/railties-4.2.5/lib/rails/commands/commands_tasks.rb:39:in `run_command!'
    from /Users/jmayer/.rvm/gems/ruby-2.3.1/gems/railties-4.2.5/lib/rails/commands.rb:17:in `<top (required)>'
    from bin/rails:4:in `require'
    from bin/rails:4:in `<main>'

rails -v
Rails 4.2.5

ruby -v
ruby 2.3.1p112 (2016-04-26 revision 54768) [x86_64-darwin18]

我已经尝试了我在堆栈溢出中发现的所有关于错误的方法，但没有运气。

我只是想启动一个开发服务器、创建一个数据库等。

【问题讨论】：

我有同样的问题 Rails 5.2.2 - ruby 2.6.1p33 (2019-01-30 revision 66950) [x86_64-darwin18] 和 mysql2 (0.5.2) bundle exec rails s 不起作用（我已经执行了 bundle 并在我的 gemfile gem 'mysql2', '>= 0.4.4', '< 0.6.0' 中进行了关注跨度>

标签： ruby-on-rails mysql2

【解决方案1】：

由于您使用的是bundle exec，它只考虑了宝石存在于 Gemfile 中，所以你需要把它放在那里。

包括

gem mysql2

在您的 Gemfile 中（位于项目的根目录中）

然后运行

bundle install

然后就可以运行了

bundle exec rails s

【讨论】：

感谢您的回复，很遗憾有很多细节我没有列出。 mysql2 在 gemfile 中。在运行gem install... 之后，我运行了bundle install。另外我在没有bundle exec的情况下运行rails s