Ruby程序中创建和解析XML文件的方法_ruby专题_

 gem install builder 

 require 'builder' x = Builder::XmlMarkup.new(:target => $stdout, :indent => 1) #":target =＞$stdout"参数：指示输出内 容将被写向标准输出控制台 #":indent =＞1"参数：XML输出形式将被缩 进一个空格字符x.instruct! :xml, :version =>'1.1',:encoding => 'gb2312' x.comment! "书本信息" x.library("shelf" => "Recent Acquisitions") { x.section("name" => "ruby"){ x.book("isbn" => "0672310001"){ x.title "Programming Ruby" x.author "Yukihiro " x.description "Programming Ruby - The Pragmatic Programmer's Guide" } } } 

< ?xml version="1.1" encoding="gb2312"?>< !-- 书本信息 -->< library shelf="Recent Acquisitions">< section name="ruby">< book isbn="0672310001">< title>Programming Ruby< /title>< author>Yukihiro < /author>< description>Programming Ruby - The Pragmatic Programmer's Guide < /description>< /book>< /section>< /library>< inspect/> #< IO:0x2a06ae8>

Hal Fulton Second edition. The book you are now reading. Ain't recursion grand? 
Robert ZubrinPushing toward a second home for the human race. James R. HansenDefinitive biography of the first man on the moon. 

 require 'rexml/document' include REXML input = File.new("books.xml") doc = Document.new(input) root = doc.root puts root.attributes["shelf"] # Recent Acquisitions doc.elements.each("library/section") { |e| puts e.attributes["name"] } # Output: # Ruby # Space doc.elements.each("*/section/book") { |e| puts e.attributes["isbn"] } # Output: # 0672328844 # 0321445619 # 0684835509 # 074325631X sec2 = root.elements[2] author = sec2.elements[1].elements["author"].text # Robert Zubrin 

 require 'rexml/document' require 'rexml/streamlistener' include REXML class MyListener include REXML::StreamListener def tag_start(*args) puts "tag_start: #{args.map {|x| x.inspect}.join(', ')}" end def text(data) return if data =~ /^\w*$/ # whitespace only abbrev = data[0..40] + (data.length > 40 ? "..." : "") puts " text : #{abbrev.inspect}" end end list = MyListener.new source = File.new "books.xml" Document.parse_stream(source, list) 

 tag_start: "library", {"shelf"=>"Recent Acquisitions"} tag_start: "section", {"name"=>"Ruby"} tag_start: "book", {"isbn"=>"0672328844"} tag_start: "title", {} text : "The Ruby Way" ......................................... 

 book1 = XPath.first(doc, "//book") # Info for first book found p book1 # Print out all titles XPath.each(doc, "//title") { |e| puts e.text } # Get an array of all of the "author" elements in the document. names = XPath.match(doc, "//author").map {|x| x.text } p names 

 ...  The Ruby Way The Case for Mars First Man: The Life of Neil A. Armstrong ["Hal Fulton", "Robert Zubrin", "James R. Hansen"]