在 localhost 上运行 rails 应用程序

Question

大家好，这里是菜鸟问题。 我在启动 rails s 时遇到问题。我认为这是一个 mysql 问题，但是当我检查 gemfile 文件中的 gem 'mysql' 时，它就在那里。

我在下面粘贴控制台日志：

$ rails s
=> Booting WEBrick
=> Rails 3.2.2 application starting in development on http://0.0.0.0:3000
=> Call with -d to detach
=> Ctrl-C to shutdown server
/Users/username/Sites/projectname/config/initializers/omniauth.rb:2: warning: already initialized constant VERIFY_PEER
[2012-05-19 18:33:15] INFO  WEBrick 1.3.1
[2012-05-19 18:33:15] INFO  ruby 1.9.3 (2012-04-20) [x86_64-darwin11.3.0]
[2012-05-19 18:33:15] INFO  WEBrick::HTTPServer#start: pid=74815 port=3000


Started GET "/" for 127.0.0.1 at 2012-05-19 18:33:30 -0400

NoMethodError (undefined method `init' for Mysql:Class):
activerecord (3.2.2) lib/active_record/connection_adapters/mysql_adapter.rb:32:in `mysql_connection'
activerecord (3.2.2) lib/active_record/connection_adapters/abstract/connection_pool.rb:277:in `new_connection'
activerecord (3.2.2) lib/active_record/connection_adapters/abstract/connection_pool.rb:287:in `checkout_new_connection'
activerecord (3.2.2) lib/active_record/connection_adapters/abstract/connection_pool.rb:235:in `block (2 levels) in checkout'
activerecord (3.2.2) lib/active_record/connection_adapters/abstract/connection_pool.rb:230:in `loop'
activerecord (3.2.2) lib/active_record/connection_adapters/abstract/connection_pool.rb:230:in `block in checkout'
/Users/gorteks/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/monitor.rb:211:in `mon_synchronize'
activerecord (3.2.2) lib/active_record/connection_adapters/abstract/connection_pool.rb:229:in `checkout'
activerecord (3.2.2) lib/active_record/connection_adapters/abstract/connection_pool.rb:95:in `connection'
activerecord (3.2.2) lib/active_record/connection_adapters/abstract/connection_pool.rb:374:in `retrieve_connection'
activerecord (3.2.2) lib/active_record/connection_adapters/abstract/connection_specification.rb:168:in `retrieve_connection'
activerecord (3.2.2) lib/active_record/connection_adapters/abstract/connection_specification.rb:142:in `connection'
activerecord (3.2.2) lib/active_record/query_cache.rb:67:in `rescue in call'
activerecord (3.2.2) lib/active_record/query_cache.rb:61:in `call'
activerecord (3.2.2) lib/active_record/connection_adapters/abstract/connection_pool.rb:443:in `call'
actionpack (3.2.2) lib/action_dispatch/middleware/callbacks.rb:28:in `block in call'
activesupport (3.2.2) lib/active_support/callbacks.rb:405:in `_run__2560155742155290980__call__1944809023615832682__callbacks'
activesupport (3.2.2) lib/active_support/callbacks.rb:405:in `__run_callback'
activesupport (3.2.2) lib/active_support/callbacks.rb:385:in `_run_call_callbacks'
activesupport (3.2.2) lib/active_support/callbacks.rb:81:in `run_callbacks'
actionpack (3.2.2) lib/action_dispatch/middleware/callbacks.rb:27:in `call'
actionpack (3.2.2) lib/action_dispatch/middleware/reloader.rb:65:in `call'
actionpack (3.2.2) lib/action_dispatch/middleware/remote_ip.rb:31:in `call'
actionpack (3.2.2) lib/action_dispatch/middleware/debug_exceptions.rb:16:in `call'
actionpack (3.2.2) lib/action_dispatch/middleware/show_exceptions.rb:56:in `call'
railties (3.2.2) lib/rails/rack/logger.rb:26:in `call_app'
railties (3.2.2) lib/rails/rack/logger.rb:16:in `call'
actionpack (3.2.2) lib/action_dispatch/middleware/request_id.rb:22:in `call'
rack (1.4.1) lib/rack/methodoverride.rb:21:in `call'
rack (1.4.1) lib/rack/runtime.rb:17:in `call'
activesupport (3.2.2) lib/active_support/cache/strategy/local_cache.rb:72:in `call'
rack (1.4.1) lib/rack/lock.rb:15:in `call'
actionpack (3.2.2) lib/action_dispatch/middleware/static.rb:61:in `call'
railties (3.2.2) lib/rails/engine.rb:479:in `call'
railties (3.2.2) lib/rails/application.rb:220:in `call'
rack (1.4.1) lib/rack/content_length.rb:14:in `call'
railties (3.2.2) lib/rails/rack/log_tailer.rb:14:in `call'
rack (1.4.1) lib/rack/handler/webrick.rb:59:in `service'
/Users/gorteks/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/webrick/httpserver.rb:138:in `service'
/Users/gorteks/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/webrick/httpserver.rb:94:in `run'
/Users/gorteks/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/webrick/server.rb:191:in `block in start_thread'


Rendered /Users/gorteks/.rvm/gems/ruby-1.9.3-p194/gems/actionpack-3.2.2/lib/action_dispatch/middleware/templates/rescues/_trace.erb (1.6ms)
Rendered /Users/gorteks/.rvm/gems/ruby-1.9.3-p194/gems/actionpack-3.2.2/lib/action_dispatch/middleware/templates/rescues/_request_and_response.erb (1.7ms)
Rendered /Users/gorteks/.rvm/gems/ruby-1.9.3-p194/gems/actionpack-3.2.2/lib/action_dispatch/middleware/templates/rescues/diagnostics.erb within rescues/layout (8.7ms)

访问本地主机时，我看到：

NoMethodError

undefined method `init' for Mysql:Class

Rails.root: /Users/username/Sites/projectname
Application Trace | Framework Trace | Full Trace

Request

Parameters:

None

Show session dump

Show env dump
Response

Headers:

None

感谢您的帮助！我被困住了！

Answer 1

您应该使用mysql2 gem 代替mysql gem 来代表您正在使用的Rails 版本。只需进行该切换即可解决您的问题。