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REXML是处理,解析XML的包,是Ruby自带的包。因为支持XPath表达式的查询,所以用来查询结点,解析XML非常方便。
通过最近做项目对解析和处理XML有如下认识:
REXML功能非常强大,但是使用上不是特别的方便,Rails把它封装了一下,生成XML非常容易,代码也很简单直观。
但对于解析XML,用REXML就可以了,十分方便并且灵活。转载自:ruby
生成XML,用Rails的Builder::XmlMarkup比较方便(rjs模板好像就用这个,由于项目需要生成XML字符后直接传给另一个方法,所以用不了rjs)
以下示例引用<< rogrammingRuby 1.9>>
- <classes language="ruby">
- <class name="Numeric">
- Numeric represents all numbers.
- <class name="Float">
- Floating point numbers have a fraction and a mantissa.
- </class>
- <class name="Integer">
- Integers contain exact integral values.
- <class name="Fixnum">
- Fixnums are stored as machine ints.
- </class>
- <class name="Bignum">
- Bignums store arbitraty-sized integers.
- </class>
- </class>
- </class>
- </classes>
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- require 'rexml/document'
- xml = REXML::Document.new(File.open("demo.xml"))
-
- puts "Root element: #{xml.root.name}"
- puts "\nThe names of all classes"
- xml.elements.each("//class") {|c| puts c.attributes["name"] }
- puts "\nThe description of Fixnum"
- p xml.elements["//class[@name='Fixnum']"].text
- produces:
- Root element: classes
- The names of all classes
- Numeric
- Float
- Integer
- Fixnum
- Bignum
- The description of Fixnum
- "\n Fixnums are stored as machine ints.\n "
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以下示例来源Rails API Builder::XmlMarkup
- xm.instruct! # <?xml version="1.0" encoding="UTF-8"?>
- xm.html { # <html>
- xm.head { # <head>
- xm.title("History") # <title>History</title>
- } # </head>
- xm.body { # <body>
- xm.comment! "HI" # <! -- HI -->
- xm.h1("Header") # <h1>Header</h1>
- xm.p("paragraph") # <p>paragraph</p>
- } # </body>
- } # </html>
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