使用新应用启动rails服务器时出现以下错误：
/Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/mysql2-0.2.6/lib/mysql2/client.rb:37:in“connect”：拒绝访问用户'root'@'localhost'（使用密码：YES）（Mysql2 ::错误）
这是我的database.yml
# MySQL. Versions 4.1 and 5.0 are recommended.
#
# Install the MySQL driver:
# gem install mysql2
#
# And be sure to use new-style password hashing:
# http://dev.mysql.com/doc/refman/5.0/en/old-client.html
development:
adapter: mysql2
encoding: utf8
reconnect: false
database: group_chat_development
pool: 5
username: root
password: admin
socket: /tmp/mysql.sock
# Warning: The database defined as "test" will be erased and
# re-generated from your development database when you run "rake".
# Do not set this db to the same as development or production.
test:
adapter: mysql2
encoding: utf8
reconnect: false
database: group_chat_test
pool: 5
username: root
password: admin
socket: /tmp/mysql.sock
production:
adapter: mysql2
encoding: utf8
reconnect: false
database: group_chat_production
pool: 5
username: root
password: admin
socket: /tmp/mysql.sock
以下是完整的错误消息
MacPro:FireDemon fred$ rails s
=> Booting Mongrel
=> Rails 3.0.3 application starting in development on http://0.0.0.0:3000
=> Call with -d to detach
=> Ctrl-C to shutdown server
Exiting
/Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/mysql2-0.2.6/lib/mysql2/client.rb:37:in `connect': Access denied for user 'root'@'localhost' (using password: YES) (Mysql2::Error)
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/mysql2-0.2.6/lib/mysql2/client.rb:37:in `initialize'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/mysql2-0.2.6/lib/active_record/connection_adapters/mysql2_adapter.rb:14:in `new'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/mysql2-0.2.6/lib/active_record/connection_adapters/mysql2_adapter.rb:14:in `mysql2_connection'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/activerecord-3.0.3/lib/active_record/connection_adapters/abstract/connection_pool.rb:228:in `new_connection'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/activerecord-3.0.3/lib/active_record/connection_adapters/abstract/connection_pool.rb:236:in `checkout_new_connection'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/activerecord-3.0.3/lib/active_record/connection_adapters/abstract/connection_pool.rb:190:in `block (2 levels) in checkout'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/activerecord-3.0.3/lib/active_record/connection_adapters/abstract/connection_pool.rb:186:in `loop'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/activerecord-3.0.3/lib/active_record/connection_adapters/abstract/connection_pool.rb:186:in `block in checkout'
from /Users/fred/.rvm/rubies/ruby-1.9.2-p180/lib/ruby/1.9.1/monitor.rb:201:in `mon_synchronize'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/activerecord-3.0.3/lib/active_record/connection_adapters/abstract/connection_pool.rb:185:in `checkout'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/activerecord-3.0.3/lib/active_record/connection_adapters/abstract/connection_pool.rb:93:in `connection'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/activerecord-3.0.3/lib/active_record/connection_adapters/abstract/connection_pool.rb:316:in `retrieve_connection'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/activerecord-3.0.3/lib/active_record/connection_adapters/abstract/connection_specification.rb:97:in `retrieve_connection'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/activerecord-3.0.3/lib/active_record/connection_adapters/abstract/connection_specification.rb:89:in `connection'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/activerecord-3.0.3/lib/active_record/base.rb:1330:in `replace_bind_variables'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/activerecord-3.0.3/lib/active_record/base.rb:1317:in `sanitize_sql_array'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/activerecord-3.0.3/lib/active_record/base.rb:1224:in `sanitize_sql_for_conditions'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/activerecord-3.0.3/lib/active_record/relation/query_methods.rb:206:in `build_where'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/activerecord-3.0.3/lib/active_record/relation/query_methods.rb:77:in `where'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/activerecord-3.0.3/lib/active_record/base.rb:441:in `where'
from /Users/fred/Desktop/FireDemon/app/models/user.rb:14:in `<class:User>'
from /Users/fred/Desktop/FireDemon/app/models/user.rb:1:in `<top (required)>'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/activesupport-3.0.3/lib/active_support/dependencies.rb:454:in `load'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/activesupport-3.0.3/lib/active_support/dependencies.rb:454:in `block in load_file'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/activesupport-3.0.3/lib/active_support/dependencies.rb:596:in `new_constants_in'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/activesupport-3.0.3/lib/active_support/dependencies.rb:453:in `load_file'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/activesupport-3.0.3/lib/active_support/dependencies.rb:340:in `require_or_load'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/activesupport-3.0.3/lib/active_support/dependencies.rb:491:in `load_missing_constant'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/activesupport-3.0.3/lib/active_support/dependencies.rb:183:in `block in const_missing'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/activesupport-3.0.3/lib/active_support/dependencies.rb:181:in `each'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/activesupport-3.0.3/lib/active_support/dependencies.rb:181:in `const_missing'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/activesupport-3.0.3/lib/active_support/inflector/methods.rb:124:in `block in constantize'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/activesupport-3.0.3/lib/active_support/inflector/methods.rb:123:in `each'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/activesupport-3.0.3/lib/active_support/inflector/methods.rb:123:in `constantize'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/activesupport-3.0.3/lib/active_support/core_ext/string/inflections.rb:43:in `constantize'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/activemodel-3.0.3/lib/active_model/observing.rb:182:in `observed_class'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/activemodel-3.0.3/lib/active_model/observing.rb:175:in `observed_classes'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/activemodel-3.0.3/lib/active_model/observing.rb:195:in `observed_classes'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/activemodel-3.0.3/lib/active_model/observing.rb:191:in `initialize'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/activerecord-3.0.3/lib/active_record/observer.rb:96:in `initialize'
from /Users/fred/.rvm/rubies/ruby-1.9.2-p180/lib/ruby/1.9.1/singleton.rb:109:in `new'
from /Users/fred/.rvm/rubies/ruby-1.9.2-p180/lib/ruby/1.9.1/singleton.rb:109:in `block in instance'
from <internal:prelude>:10:in `synchronize'
from /Users/fred/.rvm/rubies/ruby-1.9.2-p180/lib/ruby/1.9.1/singleton.rb:107:in `instance'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/activemodel-3.0.3/lib/active_model/observing.rb:66:in `instantiate_observer'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/activemodel-3.0.3/lib/active_model/observing.rb:39:in `block in instantiate_observers'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/activemodel-3.0.3/lib/active_model/observing.rb:39:in `each'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/activemodel-3.0.3/lib/active_model/observing.rb:39:in `instantiate_observers'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/activerecord-3.0.3/lib/active_record/railtie.rb:83:in `block (2 levels) in <class:Railtie>'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/activesupport-3.0.3/lib/active_support/lazy_load_hooks.rb:36:in `instance_eval'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/activesupport-3.0.3/lib/active_support/lazy_load_hooks.rb:36:in `execute_hook'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/activesupport-3.0.3/lib/active_support/lazy_load_hooks.rb:26:in `on_load'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/activerecord-3.0.3/lib/active_record/railtie.rb:82:in `block in <class:Railtie>'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/activesupport-3.0.3/lib/active_support/lazy_load_hooks.rb:34:in `call'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/activesupport-3.0.3/lib/active_support/lazy_load_hooks.rb:34:in `execute_hook'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/activesupport-3.0.3/lib/active_support/lazy_load_hooks.rb:43:in `block in run_load_hooks'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/activesupport-3.0.3/lib/active_support/lazy_load_hooks.rb:42:in `each'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/activesupport-3.0.3/lib/active_support/lazy_load_hooks.rb:42:in `run_load_hooks'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/railties-3.0.3/lib/rails/application/finisher.rb:46:in `block in <module:Finisher>'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/railties-3.0.3/lib/rails/initializable.rb:25:in `instance_exec'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/railties-3.0.3/lib/rails/initializable.rb:25:in `run'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/railties-3.0.3/lib/rails/initializable.rb:50:in `block in run_initializers'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/railties-3.0.3/lib/rails/initializable.rb:49:in `each'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/railties-3.0.3/lib/rails/initializable.rb:49:in `run_initializers'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/railties-3.0.3/lib/rails/application.rb:134:in `initialize!'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/railties-3.0.3/lib/rails/application.rb:77:in `method_missing'
from /Users/fred/Desktop/FireDemon/config/environment.rb:5:in `<top (required)>'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/activesupport-3.0.3/lib/active_support/dependencies.rb:239:in `require'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/activesupport-3.0.3/lib/active_support/dependencies.rb:239:in `block in require'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/activesupport-3.0.3/lib/active_support/dependencies.rb:225:in `block in load_dependency'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/activesupport-3.0.3/lib/active_support/dependencies.rb:596:in `new_constants_in'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/activesupport-3.0.3/lib/active_support/dependencies.rb:225:in `load_dependency'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/activesupport-3.0.3/lib/active_support/dependencies.rb:239:in `require'
from /Users/fred/Desktop/FireDemon/config.ru:3:in `block in <main>'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/rack-1.2.1/lib/rack/builder.rb:46:in `instance_eval'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/rack-1.2.1/lib/rack/builder.rb:46:in `initialize'
from /Users/fred/Desktop/FireDemon/config.ru:1:in `new'
from /Users/fred/Desktop/FireDemon/config.ru:1:in `<main>'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/rack-1.2.1/lib/rack/builder.rb:35:in `eval'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/rack-1.2.1/lib/rack/builder.rb:35:in `parse_file'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/rack-1.2.1/lib/rack/server.rb:162:in `app'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/rack-1.2.1/lib/rack/server.rb:248:in `wrapped_app'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/rack-1.2.1/lib/rack/server.rb:213:in `start'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/railties-3.0.3/lib/rails/commands/server.rb:65:in `start'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/railties-3.0.3/lib/rails/commands.rb:30:in `block in <top (required)>'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/railties-3.0.3/lib/rails/commands.rb:27:in `tap'
from /Users/fred/.rvm/gems/ruby-1.9.2-p180/gems/railties-3.0.3/lib/rails/commands.rb:27:in `<top (required)>'
from script/rails:6:in `require'
from script/rails:6:in `<main>'
MacPro:FireDemon fred$
答案 0 :(得分：16)
好像您的用户无法连接到MySQL DB。在控制台中尝试以下命令：
mysql -u root -p
出现提示时，请将密码设为“admin”
如果可以，那么你应该好好去。
答案 1 :(得分：12)
config/database.yml文件中root用户的密码错误。如果忘记了密码，可以随时使用mysqladmin命令更改root用户的密码。
答案 2 :(得分：3)
development:
adapter: mysql2
database: mydb
host: localhost
username: root
password: mypass
答案 3 :(得分：1)
答案在你的问题中＆gt; MYSQL错误用户'root @ localhost'的访问被拒绝
将具有管理员密码的root用户应用于您的group_chat_development MySQL数据库
<强>更新 在我看来，您可能根本不希望为您的开发和测试数据库使用msQL，在这种情况下将您的database.yml文件测试和开发设置更改为
# SQLite version 3.x
# gem install sqlite3-ruby (not necessary on OS X Leopard)
development:
adapter: sqlite3
database: db/development.sqlite3
pool: 5
timeout: 5000
# Warning: The database defined as "test" will be erased and
# re-generated from your development database when you run "rake".
# Do not set this db to the same as development or production.
test:
adapter: sqlite3
database: db/test.sqlite3
pool: 5
timeout: 5000
如果您不知道如何使用MySQL工具，那么您应该很快习惯使用它们，因为您很可能在生产服务器环境中需要它们 您将在此处找到指向MySQL相关版本的链接http://dev.mysql.com/doc/ 使用MySQL Administrator设置用户权限。
答案 4 :(得分：1)
所以我被困了一段时间。
检查文件config / database.yml并检查您的设置。
default: &default
adapter: mysql2
encoding: utf8
pool: 5
username: root
password: root
socket: ( check what your socket location is by typing mysqladmin version into termnal)
然后进入终端并输入
mysql -u root -p
最后关闭终端并重新打开，然后
bundle instal
然后
rails s
接缝就像你必须再次捆绑安装才能进行更改。
希望有所帮助！
答案 5 :(得分：1)
这对我有用
mysql> ALTER USER 'root'@'localhost' IDENTIFIED WITH mysql_native_password BY 'your_password’;
mysql> FLUSH PRIVILEGES;
mysql> exit;
在上述命令之后尝试
mysql -u root -p
答案 6 :(得分：0)
如果您是第一次设置mysql root密码，请键入以下命令，如下所示：
mysqladmin密码
您将被提示输入新密码并确认密码。
确认后尝试使用您刚刚设置的用户root和密码登录。
mysql root @＆＃39;你的新密码＆＃39;
注意：您必须以root用户身份登录，然后才能设置mysql密码。
感谢。
答案 7 :(得分：0)
对我来说，它是通过定义用户名来解决的，而不是将其保留为空
development:
adapter: mysql2
database: my_db
encoding: utf8
username: # ADD DATABASE USERNAME
password: # ADD DATABASE PASSWORD
host: localhost
所以我将所有数据库的内容更改为以下内容
development:
adapter: mysql2
database: my_db
encoding: utf8
username: root
password: # ADD DATABASE PASSWORD
host: localhost
而且效果很好，希望这会有所帮助
答案 8 :(得分：-1)
你应该在database.yml文件的devlepment中给出“host：”字段。 主机名必须是“IP”地址，如“127.0.0.1”或某些东西.. 即“主持人：127.0.0.1” 然后重新启动服务器并输入地址，如'127.0.0.1:3000' 这里3000是港口提名者......
答案 9 :(得分：-1)
如果您使用oracle软件包安装，请尝试通过
登录您的mysqlmysql -u username
然后运行
FLUSH PRIVILEGES;
然后设置密码
SET PASSWORD FOR 'username'@'localhost' = PASSWORD('[password]');