使用 XMLTwig 進行解析

#!/usr/bin/env perl

use strict;
use warnings 'all';

use XML::Twig;

my $twig = XML::Twig->parse( \*DATA );

#we can use the 'root' method to find the root of the XML.
my $root = $twig->root;

#first_child finds the first child element matching a value.
my $title = $root->first_child('title');

#text reads the text of the element.
my $title_text = $title->text;

print "Title is: ", $title_text, "\n";

#The above could be combined:
print $twig ->root->first_child_text('title'), "\n";

## You can use the 'children' method to iterate multiple items:
my $list = $twig->root->first_child('list');

#children can optionally take an element 'tag' - otherwise it just returns all of them.
foreach my $element ( $list->children ) {

   #the 'att' method reads an attribute
   print "Element with ID: ", $element->att('id') // 'none here', " is ", $element->text,
     "\n";
}

#And if we need to do something more complicated, we an use 'xpath'.
#get_xpath or findnodes do the same thing:
#return a list of matches, or if you specify a second numeric argument, just that numbered match.

#xpath syntax is fairly extensive, but in this one - we search:
# anywhere in the tree: //
#nodes called 'item'
#with an id attribute [@id]
#and with that id attribute equal to "1000". 
#by specifying '0' we say 'return just the first match'.

print "Item 1000 is: ", $twig->get_xpath( '//item[@id="1000"]', 0 )->text, "\n";

#this combines quite well with `map` to e.g. do the same thing on multiple items
print "All IDs:\n", join ( "\n", map { $_ -> att('id') } $twig -> get_xpath('//item')); 
#note how this also finds the item under 'summary', because of //

__DATA__
<?xml version="1.0" encoding="utf-8"?>
<root>
  <title>some sample xml</title>
  <first key="value" key2="value2">
    <second>Some text</second>
  </first>
  <third>
    <fourth key3="value">Text here too</fourth>
  </third>
  <list>
     <item id="1">Item1</item>
     <item id="2">Item2</item>
     <item id="3">Item3</item>
     <item id="66">Item66</item>
     <item id="88">Item88</item>
     <item id="100">Item100</item>
     <item id="1000">Item1000</item>
     <notanitem>Not an item at all really.</notanitem>
  </list>
  <summary>
     <item id="no_id">Test</item>
  </summary>
</root>