在perl中将父元素添加到xml文档

Question

我在向xml文档添加父级时遇到了一个问题。我得到了xml：

<book id="bk104">
  <author>Corets, Eva</author>
  <title>Oberon's Legacy</title>
  <genre>Fantasy</genre>
  <price>5.95</price>
  <publish_date>2001-03-10</publish_date>
  <description>In post-apocalypse England, the mysterious 
  agent known only as Oberon helps to create a new life 
  for the inhabitants of London. Sequel to Maeve 
  Ascendant.</description>
</book>

我想要向图书添加parent标签，因此它将是：

<library>
 <book id="bk104">
  <author>Corets, Eva</author>
  <title>Oberon's Legacy</title>
  <genre>Fantasy</genre>
  <price>5.95</price>
  <publish_date>2001-03-10</publish_date>
  <description>In post-apocalypse England, the mysterious 
  agent known only as Oberon helps to create a new life 
  for the inhabitants of London. Sequel to Maeve 
  Ascendant.</description>
 </book>
</library>

我正在使用XML::LIBXML，我已经尝试进入根目录

my $root = $doc->getDocumentElement;

并创建新元素

my $new_element= $doc->createElement("library");

然后

$root->insertBefore($new_element,undef);

最后：

my $root = $doc->getDocumentElement;
my $new_element= $doc->createElement("library");
$parent = $root->parentNode;
$root->insertBefore($new_element,$parent);

但这行不通。我还试图找到返回header节点的根的父节点，然后addchild，但也不起作用。

Answer 1

您需要创建一个新的空library元素，并将其设置为文档的新根元素。然后将旧的根添加为新的子级。

use strict;
use warnings;

use XML::LibXML;

my $doc = XML::LibXML->load_xml(string => << '__END_XML__');
<book id="bk104">
  <author>Corets, Eva</author>
  <title>Oberon's Legacy</title>
  <genre>Fantasy</genre>
  <price>5.95</price>
  <publish_date>2001-03-10</publish_date>
  <description>In post-apocalypse England, the mysterious 
  agent known only as Oberon helps to create a new life 
  for the inhabitants of London. Sequel to Maeve 
  Ascendant.</description>
</book>
__END_XML__

my $book = $doc->documentElement;
my $library = $doc->createElement('library');
$doc->setDocumentElement($library);
$library->appendChild($book);

print $doc->toString(1);

输出

<?xml version="1.0"?>
<library>
  <book id="bk104">
    <author>Corets, Eva</author>
    <title>Oberon's Legacy</title>
    <genre>Fantasy</genre>
    <price>5.95</price>
    <publish_date>2001-03-10</publish_date>
    <description>In post-apocalypse England, the mysterious 
  agent known only as Oberon helps to create a new life 
  for the inhabitants of London. Sequel to Maeve 
  Ascendant.</description>
  </book>
</library>