无法使用rackup和jRuby启动简单的Sinatra应用程序(Web服务器无响应)

我有一个Sinatra"hello world"应用程序，正在尝试使用jRuby运行.当我运行应用程序时，它起作用，但是当我运行机架式测试时，它不起作用.谁能告诉我这是怎么回事?

I've got a Sinatra "hello world" app that I am trying to run using jRuby. It works when I run the app, but not when I run rackup. Can anyone tell me what is going on here?

以下是该应用程序，位于文件"app.rb"中:

Here's the app, in a file 'app.rb':

require 'rubygems'
require 'bundler/setup'
require 'sinatra'

configure do
  set :bind, '0.0.0.0'
end

get '/' do
  'Boo!'
end

我可以使用bundle exec ruby app.rb运行它，并且工作正常:

I can run this using bundle exec ruby app.rb and it works fine:

jonea@centos7andy[~/andy/sinatra_sand_jruby]%: bundle exec ruby app.rb
[2015-01-12 10:36:06] INFO  WEBrick 1.3.1
[2015-01-12 10:36:06] INFO  ruby 1.9.3 (2014-12-09) [java]
== Sinatra/1.4.5 has taken the stage on 4567 for development with backup from WEBrick
[2015-01-12 10:36:06] INFO  WEBrick::HTTPServer#start: pid=31654 port=4567

这是我的config.ru，用于调用上述程序:

Here is my config.ru to call the above program:

require 'rubygems'
require 'bundler/setup'
require 'sinatra'
require './app'

run Sinatra::Application

如果运行此命令，它似乎可以工作，但是我无法使用网络浏览器访问服务器:

If I run this, it appears to work, but I can't access the server using a web browser:

jonea@centos7andy[~/andy/sinatra_sand_jruby]%: bundle exec rackup -p4567
[2015-01-12 10:29:06] INFO  WEBrick 1.3.1
[2015-01-12 10:29:06] INFO  ruby 1.9.3 (2014-12-09) [java]
[2015-01-12 10:29:06] INFO  WEBrick::HTTPServer#start: pid=31553 port=4567

我注意到"Sinatra已经登台……"的可疑之处.

I note the suspicious lack of "Sinatra has taken the stage..."