jruby下使用nokogiri、xslt

jruby与原生的ruby vm之间最大的区别是多了一个jvm作为中间层，好处是可以借助成熟的java 虚拟机技术，缺点就是不能象以前那样使用很多本地编译的动态链接库，这个问题的解决只能靠为这些库开发java版本来搞定。

 

例如，很多ruby开发者都喜欢nokogiri这个库，它处理html、xml非常方便，但是之前它是基于本地库的，所以jruby环境下不好用，不过现在有了 java 版本

 

$ gem list nokogiri
*** LOCAL GEMS ***
nokogiri (1.4.4.2 java)

 

不过，实际使用的时候还有一个问题，它需要有xslt哭的支持，否则就会出错：

 

$ rails s
/home/john/.rvm/rubies/jruby-1.5.6/lib/ruby/site_ruby/shared/ffi/library.rb:28:in `ffi_lib': Could not
 open library 'xslt' : xslt: cannot open shared object file: No such file or directory. Could not open 
library 'libxslt.so' : libxslt.so: cannot open shared object file: No such file or directory (LoadError)
	from /home/john/.rvm/rubies/jruby-1.5.6/lib/ruby/site_ruby/shared/ffi/library.rb:10:in `map'
	from /home/john/.rvm/rubies/jruby-1.5.6/lib/ruby/site_ruby/shared/ffi/library.rb:10:in `ffi_lib'
	from /home/john/.rvm/gems/jruby-1.5.6/gems/nokogiri-1.4.4.2-java/lib/nokogiri/ffi/libxml.rb:13
	from /home/john/.rvm/gems/jruby-1.5.6/gems/nokogiri-1.4.4.2-java/lib/nokogiri/ffi/libxml.rb:239
:in `require'
 

 

但是 ruby-xslt 是不能用在这里的，因为它也不是纯ruby库，因此不能用在jruby上

 

$ gem install ruby-xslt
Building native extensions.  This could take a while...
ERROR:  Error installing ruby-xslt:
	ERROR: Failed to build gem native extension.

        /home/john/.rvm/rubies/jruby-1.5.6/bin/jruby extconf.rb
WARNING: JRuby does not support native extensions or the `mkmf' library.
         Check http://kenai.com/projects/jruby/pages/Home for alternatives.
extconf.rb:31: undefined method `enable_config' for main:Object (NoMethodError)

 

最后找到的是这个库：

 

$ gem install saxony
Fetching: saxony-0.3.3.gem (100%)
Successfully installed saxony-0.3.3
1 gem installed
Installing RDoc documentation for saxony-0.3.3...
$ rails s
=> Booting WEBrick
=> Rails 3.0.5 application starting in development on http://0.0.0.0:3000
=> Call with -d to detach
=> Ctrl-C to shutdown server
[2011-05-21 11:16:11] INFO  WEBrick 1.3.1
[2011-05-21 11:16:11] INFO  ruby 1.8.7 (2010-12-03) [java]
[2011-05-21 11:16:16] INFO  WEBrick::HTTPServer#start: pid=3755 port=3000

 

ok，现在可以用 nokogiri 了