Question

我是Ruby的初学者，我制作了一些代码来学习如何使用REXML在Ruby中读取/更新XML：

这是我的代码：

# encoding: utf-8

# Programme used to store information about the state of mind of the user at different times.
# The user can later review all of his "state of mind" with the date he wrote it
require "rexml/document"
include REXML

$doc = Document.new File.new("som.xml")

def reads_old_som
  $doc.elements.each("StatesOfMind/StateOfMind") do |e|
    puts e.elements["Date"].text 
    puts e.elements["Content"].text
    puts ""
  end
end

puts "Describe your state of mind now ! (This must be between 10 and 25 words)"
content = gets.chomp
date_time = Time.now.strftime("%d/%m/%Y %H:%M")

until content.split.length.between?(10,25)
  puts "It must be between 10 & 25 words, dude !"
  puts "Rewrite me this !"
  content = gets.chomp   
  date_time = Time.now.strftime("%d/%m/%Y %H:%M")
end

som = Element.new("StateOfMind")
som.add_element "Date"
som.elements["Date"].text = date_time
som.add_element "Content"
som.elements["Content"].text = content
$doc.root.add_element som
$doc.write("som.xml", 2)

puts "Ok great ! Your state of mind was saved. Would you like to read the state of mind you wrote in the past ? (Y/N)"
choice = gets.chomp.capitalize

until choice == "Y" || choice == "N"
  puts "Please answer with Y or N"
  choice = gets.chomp.capitalize
end

if choice == "Y"
  puts "Here's all the state of mind you recorded :"
  reads_old_som
end

除了我添加的数据没有存储在XML事实中之外，一切都运行良好。显然，问题来自$ doc.write部分，但我无法弄清楚如何解决这个问题！

我在互联网上搜索过，找不到让这种方法有效的方法。伙计们，我需要你的帮助！

Answer 1

替换

$doc.write("som.xml", 2)

使用

$doc.write(File.open("som.xml","w"), 2) ## Must open File in "w" mode in order to write

以下代码仅在som.xml中存在StatesOfMind标记的情况下才有效

def reads_old_som      
  $doc.elements.each("StatesOfMind/StateOfMind") do |e| 
    puts e.elements["Date"].text 
    puts e.elements["Content"].text
    puts ""
  end
end

注意：

$doc = Document.new File.new("som.xml")表示som.xml已经存在，否则会引发错误。根据OP注释som.xml不为空，所以我相应地更新了代码。

输入XML（som.xml）：som.xml必须具有最小根元素“StatesOfMind”（Notice Plural）存在

<StatesOfMind> <StatesOfMind>

这是确切的代码

require "rexml/document" include REXML $doc = Document.new File.new("som.xml") def reads_old_som $doc.elements.each("StatesOfMind/StateOfMind") do |e| puts e.elements["Date"].text puts e.elements["Content"].text puts "" end end puts "Describe your state of mind now ! (This must be between 10 and 25 words)" content = gets.chomp date_time = Time.now.strftime("%d/%m/%Y %H:%M") until content.split.length.between?(10,25) puts "It must be between 10 & 25 words, dude !" puts "Rewrite me this !" content = gets.chomp date_time = Time.now.strftime("%d/%m/%Y %H:%M") end som = Element.new("StateOfMind") som.add_element "Date" som.elements["Date"].text = date_time som.add_element "Content" som.elements["Content"].text = content $doc.root.add_element som $doc.write(File.open("som.xml","w"), 2) puts "Ok great ! Your state of mind was saved. Would you like to read the state of mind you wrote in the past ? (Y/N)" choice = gets.chomp.capitalize until choice == "Y" || choice == "N" puts "Please answer with Y or N" choice = gets.chomp.capitalize end if choice == "Y" puts "Here's all the state of mind you recorded :" reads_old_som end

首次运行时生成的输出XML（som.xml）

<StatesOfMind> <StateOfMind> <Date> 17/03/2014 16:30 </Date> <Content> Hi This is Kirti How are you doing Nice to meet you. </Content> </StateOfMind> <StatesOfMind>

在第二次运行时生成的输出XML（som.xml）

<StatesOfMind> <StateOfMind> <Date> 17/03/2014 16:30 </Date> <Content> Hi This is Kirti How are you doing Nice to meet you. </Content> </StateOfMind> <StateOfMind> <Date> 17/03/2014 16:32 </Date> <Content> Hi This is John Doe Nice to meet you. I am doing great. </Content> </StateOfMind> <StatesOfMind>

使用REXML读取，编辑和保存现有XML文件

1 个答案: