向XML::LibXML对象添加新的节点/元素

Question

下面是一个基本的XML文档示例

<book_reviewers>
    <results>
        <reviewer>
            <name>Anne</name>
            <profession>Catfish wrangler</profession>
        </reviewer>
        <reviewer>
            <name>Bob</name>
            <profession>Beer taster</profession>
        </reviewer>
        <reviewer>
            <name>Charlie</name>
            <profession>Gardener</profession>
        </reviewer>
    </results>
</book_reviewers>

我想加上这个:

<reviewer>
    <name>Joan</name>
    <profession>Jett</profession>
 </reviewer>

我已经尝试了许多解决方案的组合，这里有一个，至少，不会抛出错误，但是，它也不起作用。

#!/usr/bin/perl
use XML::LibXML;
use strict;
my $filename = "cr.xml";
my $parser = XML::LibXML->new();
my $critic_details = $parser->parse_file("$filename") or die;
my $new_reviewer = $critic_details->documentElement;
my $reviewer_name = $critic_details->documentElement;
my $reviewer_prof = $critic_details->documentElement;
my $newnode = $critic_details->documentElement;
 for my $reviewers($critic_details->findnodes("book_reviewers/results/reviewers")){
     $new_reviewer = $reviewers->createElement("reviewer");
    $reviewer_name = $new_reviewer->addChild("name");
    $reviewer_name->appendText("Joan");
    $reviewer_prof = $new_reviewer->addChild("profession");
    $reviewer_prof->appendText("Jett");
    $newnode = $reviewers->addSibling($new_reviewer); #also tried addChild
}
print $critic_details->toString;

我得到的输出是:

<?xml version="1.0"?>
<book_reviewers>
        <results>
                <reviewer>
                        <name>Anne</name>
                        <profession>Catfish wrangler</profession>
                </reviewer>
                <reviewer>
                        <name>Bob</name>
                        <profession>Beer taster</profession>
                </reviewer>
                <reviewer>
                        <name>Charlie</name>
                        <profession>Gardener</profession>
                </reviewer>
        </results>
</book_reviewers>

就是原始数据

非常感谢任何帮助-我对Perl和XML都很陌生欢呼声

Answer 1

有很多方法可以做到这一点

这种方式分别创建节点并将其放在一起。它还没有为生产做好准备，因为它假设有一个

节。

#!/usr/bin/perl
use XML::LibXML;
use strict;
my $filename = "cr.xml";
my $parser = XML::LibXML->new();
my $critic_details = $parser->parse_file("$filename") or die;
my $reviewer  = $critic_details->findnodes("book_reviewers/results")->[0];
my $node = XML::LibXML::Element->new("reviewer");
my $p = XML::LibXML::Element->new("profession");
my $pn = XML::LibXML::Text->new("Jett");
$p->addChild($pn);
my $n = XML::LibXML::Element->new("name");
my $nn = XML::LibXML::Text->new("Joan");
$n->addChild($nn);
$node->addChild($p);
$node->addChild($n);
$reviewer->addChild($node);
print $critic_details->toString;

给出

<?xml version="1.0"?>
<book_reviewers>
    <results>
        <reviewer>
            <name>Anne</name>
            <profession>Catfish wrangler</profession>
        </reviewer>
        <reviewer>
            <name>Bob</name>
            <profession>Beer taster</profession>
        </reviewer>
        <reviewer>
            <name>Charlie</name>
            <profession>Gardener</profession>
        </reviewer>
    <reviewer><profession>Jett</profession><name>Joan</name></reviewer></results>
</book_reviewers>

Answer 2

只是为了帮助您了解XML::LibXML的一些更整洁的东西，并让您更容易地理解XML是如何工作的，我在这里发布了另一个答案。也许你也能从中找到一些有用的线索:

use strict;
use warnings;
use utf8;
use XML::LibXML;
my $filename = "cr.xml";
my $parser = XML::LibXML->new();
my $critic_details = $parser->parse_file("$filename") or die;
# find ALL the <book_reviewers><results> nodes
my @results = $critic_details->findnodes("book_reviewers/results");
die "no result node in xml-file" unless @results;
my ($name, $profession) = ("Joan", "Jett");
#
# Here gets the work done, put this in a loop for more entries
#
# add a new <reviewer> node to the LAST <results>
my $reviewer_node_child;
my $reviewer_node = $results[-1]->addNewChild(undef, "reviewer");
# create a child node
$reviewer_node_child =  $reviewer_node->addNewChild(undef, "name");
$reviewer_node_child->appendTextNode($name);
# create a child node
$reviewer_node_child =  $reviewer_node->addNewChild(undef, "profession");
$reviewer_node_child->appendTextNode($profession);
#
# Done the heavy power lifting
#
use XML::LibXML::PrettyPrint;
my $pretty = XML::LibXML::PrettyPrint->new(
  indent_string => ' ' x4,
  element       => {
    compact       => [qw| name profession | ],
    }
  );
$pretty->pretty_print($critic_details);
print $critic_details->toString;
__END__

这里需要addNewChild方法中的undef。它们用于设置xml名称空间，这里不需要，但在大型xml文档中确实是这样做的。

另外，我添加XML::LibXML::PrettyPrint只是为了向您展示如何回到漂亮的语法。请原谅我在脚本末尾添加了use…。

产生如下结果:

<?xml version="1.0"?>
<book_reviewers>
    <results>
        <reviewer>
            <name>Anne</name>
            <profession>Catfish wrangler</profession>
        </reviewer>
        <reviewer>
            <name>Bob</name>
            <profession>Beer taster</profession>
        </reviewer>
        <reviewer>
            <name>Charlie</name>
            <profession>Gardener</profession>
        </reviewer>
        <reviewer>
            <name>Joan</name>
            <profession>Jett</profession>
        </reviewer>
    </results>
</book_reviewers>

享受XML和Perl，一个非常强大但令人畏惧的工具组合!

Answer 3

可以使用XML::LibXML将节点从一个XML文档导入到另一个XML文档。这很有用，因为您不必使用对象显式地构建新数据，而只需使用标准的XML表示法即可。

下面的代码演示了这一点。通过在新文档中设置根节点，然后遍历找到的节点，而不是只选择第一个，可以很容易地扩展到重要的多个新审阅者。

#!/usr/bin/perl
use strict;
use warnings;
use XML::LibXML;
my $dom = XML::LibXML->load_xml(IO => *DATA);
my $newnode = XML::LibXML->load_xml(string => <<'END_STRING')->findnodes('//*')->[0];
<reviewer>
    <name>Joan</name>
    <profession>Jett</profession>
</reviewer>
END_STRING
$dom->findnodes("book_reviewers/results")->[0]->addChild($newnode);
print $dom->toString;
__DATA__
<book_reviewers>
    <results>
        <reviewer>
            <name>Anne</name>
            <profession>Catfish wrangler</profession>
        </reviewer>
        <reviewer>
            <name>Bob</name>
            <profession>Beer taster</profession>
        </reviewer>
        <reviewer>
            <name>Charlie</name>
            <profession>Gardener</profession>
        </reviewer>
    </results>
</book_reviewers>

输出:

<?xml version="1.0"?>
<book_reviewers>
    <results>
        <reviewer>
            <name>Anne</name>
            <profession>Catfish wrangler</profession>
        </reviewer>
        <reviewer>
            <name>Bob</name>
            <profession>Beer taster</profession>
        </reviewer>
        <reviewer>
            <name>Charlie</name>
            <profession>Gardener</profession>
        </reviewer>
    <reviewer>
    <name>Joan</name>
    <profession>Jett</profession>
</reviewer></results>
</book_reviewers>