ruby on rails不会加载欢迎页面（localhost：3000）

Question

我刚刚安装了RoR，一切似乎都很好。 但是，当我最终加载所有内容时，要启动页面localhost:3000我首先在命令提示符下得到此错误：

C:\ruby\rails\firstapp>rails server
C:/ruby/lib/ruby/gems/2.1.0/gems/bundler-1.13.0.pre.1/lib/bundler/runtime.rb:89:
in `rescue in block (2 levels) in require': There was an error while trying to load the gem 'uglifier'. (Bundler::GemRequireError)
Gem Load Error is: Could not find a JavaScript runtime. See https://github.com/rails/execjs for a list of available runtimes.
Backtrace for gem load error is:
C:/ruby/lib/ruby/gems/2.1.0/gems/execjs-2.7.0/lib/execjs/runtimes.rb:58:in `autodetect'
C:/ruby/lib/ruby/gems/2.1.0/gems/execjs-2.7.0/lib/execjs.rb:5:in `<module:ExecJS>'
C:/ruby/lib/ruby/gems/2.1.0/gems/execjs-2.7.0/lib/execjs.rb:4:in `<top (required)>'
C:/ruby/lib/ruby/gems/2.1.0/gems/uglifier-3.0.0/lib/uglifier.rb:5:in `require'
C:/ruby/lib/ruby/gems/2.1.0/gems/uglifier-3.0.0/lib/uglifier.rb:5:in `<top (required)>'
C:/ruby/lib/ruby/gems/2.1.0/gems/bundler-1.13.0.pre.1/lib/bundler/runtime.rb:86:
in `require'
C:/ruby/lib/ruby/gems/2.1.0/gems/bundler-1.13.0.pre.1/lib/bundler/runtime.rb:86:
in `block (2 levels) in require'
C:/ruby/lib/ruby/gems/2.1.0/gems/bundler-1.13.0.pre.1/lib/bundler/runtime.rb:81:
in `each'
C:/ruby/lib/ruby/gems/2.1.0/gems/bundler-1.13.0.pre.1/lib/bundler/runtime.rb:81:
in `block in require'
C:/ruby/lib/ruby/gems/2.1.0/gems/bundler-1.13.0.pre.1/lib/bundler/runtime.rb:70:
in `each'
C:/ruby/lib/ruby/gems/2.1.0/gems/bundler-1.13.0.pre.1/lib/bundler/runtime.rb:70:
in `require'
C:/ruby/lib/ruby/gems/2.1.0/gems/bundler-1.13.0.pre.1/lib/bundler.rb:104:in `req
uire'
C:/ruby/rails/firstapp/config/application.rb:7:in `<top (required)>'
C:/ruby/lib/ruby/gems/2.1.0/gems/railties-4.2.6/lib/rails/commands/commands_task
s.rb:78:in `require'
C:/ruby/lib/ruby/gems/2.1.0/gems/railties-4.2.6/lib/rails/commands/commands_task
s.rb:78:in `block in server'
C:/ruby/lib/ruby/gems/2.1.0/gems/railties-4.2.6/lib/rails/commands/commands_task
s.rb:75:in `tap'
C:/ruby/lib/ruby/gems/2.1.0/gems/railties-4.2.6/lib/rails/commands/commands_task
s.rb:75:in `server'
C:/ruby/lib/ruby/gems/2.1.0/gems/railties-4.2.6/lib/rails/commands/commands_task
s.rb:39:in `run_command!'
C:/ruby/lib/ruby/gems/2.1.0/gems/railties-4.2.6/lib/rails/commands.rb:17:in `<to
p (required)>'
bin/rails:4:in `require'
bin/rails:4:in `<main>'
Bundler Error Backtrace:
        from C:/ruby/lib/ruby/gems/2.1.0/gems/bundler-1.13.0.pre.1/lib/bundler/r
untime.rb:85:in `block (2 levels) in require'
        from C:/ruby/lib/ruby/gems/2.1.0/gems/bundler-1.13.0.pre.1/lib/bundler/r
untime.rb:81:in `each'
        from C:/ruby/lib/ruby/gems/2.1.0/gems/bundler-1.13.0.pre.1/lib/bundler/r
untime.rb:81:in `block in require'
        from C:/ruby/lib/ruby/gems/2.1.0/gems/bundler-1.13.0.pre.1/lib/bundler/r
untime.rb:70:in `each'
        from C:/ruby/lib/ruby/gems/2.1.0/gems/bundler-1.13.0.pre.1/lib/bundler/r
untime.rb:70:in `require'
        from C:/ruby/lib/ruby/gems/2.1.0/gems/bundler-1.13.0.pre.1/lib/bundler.r
b:104:in `require'
        from C:/ruby/rails/firstapp/config/application.rb:7:in `<top (required)>
'
        from C:/ruby/lib/ruby/gems/2.1.0/gems/railties-4.2.6/lib/rails/commands/
commands_tasks.rb:78:in `require'
        from C:/ruby/lib/ruby/gems/2.1.0/gems/railties-4.2.6/lib/rails/commands/
commands_tasks.rb:78:in `block in server'
        from C:/ruby/lib/ruby/gems/2.1.0/gems/railties-4.2.6/lib/rails/commands/
commands_tasks.rb:75:in `tap'
        from C:/ruby/lib/ruby/gems/2.1.0/gems/railties-4.2.6/lib/rails/commands/
commands_tasks.rb:75:in `server'
        from C:/ruby/lib/ruby/gems/2.1.0/gems/railties-4.2.6/lib/rails/commands/
commands_tasks.rb:39:in `run_command!'
        from C:/ruby/lib/ruby/gems/2.1.0/gems/railties-4.2.6/lib/rails/commands.
rb:17:in `<top (required)>'
        from bin/rails:4:in `require'
        from bin/rails:4:in `<main>'
C:\ruby\rails\firstapp>

之后，我搜索页面localhost:3000 ，仅显示页面错误。

虽然问题出在红宝石，但我将其卸载了，更改了版本（我现在使用2.1.8），但仍然无济于事。 请问我真的需要帮助吗？

Answer 1

您使用OSX还是Linux？

osx： brew install nodejs

linux： sudo apt-get install nodejs

如果您从Windows执行此操作，上帝会帮助您。

Answer 2

您需要为Javascript运行时安装nodejs

https://nodejs.org/en/download/

Answer 3

问题是您的环境缺少JavaScript运行时。 可以是其他答案所建议的node.js ，但不限node.js 。

Execjs支持：

• Therubyracer
• Node.js
• JScript（Windows脚本主机）
• 除其他外 。

因此，您实际上可以使用一种非常适合您的环境的运行时。