Ruby使用REXML库来解析xml格式数据的方法
REXML 是一个完全用ruby写的processor,他有多种api,其中两个经典的api是通过DOM-like 和SAX-like 来进行区分的。第一种是将整个文件读进内存,然后存储为一个分层的形式(也就是一棵树了).而第二种是"parse as you go",当你的文件很大,并且内存受到限制的时候,比较适合用这种。
下面我们来看看如何使用它,假设我们有如下xml文件: <collection shelf="New Arrivals"> <movie title="Enemy Behind"> <type>War,Thriller</type> <format>DVD</format> <year>2003</year> <rating>PG</rating> <stars>10</stars> <description>Talk about a US-Japan war</description> </movie> <movie title="Transformers"> <type>Anime,Science Fiction</type> <format>DVD</format> <year>1989</year> <rating>R</rating> <stars>8</stars> <description>A schientific fiction</description> </movie> <movie title="Trigun"> <type>Anime,Action</type> <format>DVD</format> <episodes>4</episodes> <rating>PG</rating> <stars>10</stars> <description>Vash the Stampede!</description> </movie> <movie title="Ishtar"> <type>Comedy</type> <format>VHS</format> <rating>PG</rating> <stars>2</stars> <description>Viewable boredom</description> </movie> </collection> 解析DOM: require 'rexml/document' include REXML xmlfile = File.new("movies.xml") xmldoc = Document.new(xmlfile) root = xmldoc.root puts "Root element : " + root.attributes["shelf"] xmldoc.elements.each("collection/movie"){ |e| puts "Movie Title : " + e.attributes["title"] } xmldoc.elements.each("collection/movie/type") { |e| puts "Movie Type : " + e.text } xmldoc.elements.each("collection/movie/description") { |e| puts "Movie Description : " + e.text } 使用XPATH: require 'rexml/document' include REXML xmlfile = File.new("movies.xml") xmldoc = Document.new(xmlfile) movie = XPath.first(xmldoc,"//movie") p movie XPath.each(xmldoc,"//type") { |e| puts e.text } names = XPath.match(xmldoc,"//format").map {|x| x.text } p names 以备不时之需! PS:关于REXML的安全问题 require ‘rexml-expansion-fix' 2、Rails 2.1.0以上版本 (编辑:李大同) 【声明】本站内容均来自网络,其相关言论仅代表作者个人观点,不代表本站立场。若无意侵犯到您的权利,请及时与联系站长删除相关内容! |