使用perl修改xml标签的属性值 [英] Modifying attribute value of xml tag using perl

问题描述

我有一个很长的 xml，我希望更新其中一个嵌套很深的标签的属性值，所以不想逐个节点地进行.此外，预期节点的结构始终不同，如下所示:输入 XML 为:

I am having a very long xml and I wish to update the attribute value of one of the tag which is very deep nested so don't want to go node by node. Also structure is not same for the intended node always as can be seen below: Input XML is:

<Re>
<Co Class="Parameter" ID="CSCP001" Status="Available">
<FileSpec URL="c://mine/testfiles/wln/c.txt"/>
<CoOp Operation="Tag" SourceCS="RGB" SourceObjects="All">
<FileSpec Resource="SourceProfile" URL="c://mine/testfiles/wln/d.txt"/>
</CoOp>
</Co>
<Ru Class="Parameter" ID="IDR002" PartIDKeys="Run" Status="Available">
<Ru EndOfDocument="true" Pages="0" Run="1" RunTag="First">
<La>
<FileSpec URL="c://mine/testfiles/wln/e.txt"/>
</La>
</Ru>
</Ru>
</Re>

并且我希望输出 xml 为

and I wish to have output xml as

<Re>
<Co Class="Parameter" ID="CSCP001" Status="Available">
<FileSpec URL="d://yours/wln/c.txt"/>
<CoOp Operation="Tag" SourceCS="RGB" SourceObjects="All">
<FileSpec Resource="SourceProfile" URL="d://yours/wln/d.txt"/>
</CoOp>
</Co>
<Ru Class="Parameter" ID="IDR002" PartIDKeys="Run" Status="Available">
<Ru EndOfDocument="true" Pages="0" Run="1" RunTag="First">
<La>
<FileSpec URL="d://yours/wln/e.txt"/>
</La>
</Ru>
</Ru>
</Re>

我尝试使用 xml simple、xmllib，但无法完成所需的工作.我是 perl 编程新手.

I tried using xml simple, xmllib but not able to do the required. I am new in perl programming.

use XML::LibXML qw( );
use XML::LibXML;
use Data::Dumper;  

my $xml = "a.txt";
my $xpath_expression = 'FileSpec';

my $parser = XML::LibXML->new();
my $doc = $parser->parse_file($xml) or warn "Could not";

my $parser1 = XML::LibXML::Element->new($xml);


for my $FileSpec1 ($doc->getElementsByTagName('FileSpec')) 
{
print $FileSpec1;
my $xpath = '$FileSpec1/@URL';
my ($attr) = $doc->findnodes($xpath);    
$attr->setValue('dfdsa'); 
my ($URL1) = $FileSpec1->findvalue('@URL');
print $URL1;
}

我尝试使用 $node->setAttribute( $aname, $avalue );但这是抛出异常.请指教.

I tried using $node->setAttribute( $aname, $avalue ); but this is throwing exceptions. Please advice.

推荐答案

你的代码太复杂了.您不需要解析器，不需要元素，只需找到网址并更改它们:

Your code is too complicated. You need no parser, no elements, just find the urls and change them:

#!/usr/bin/perl
use warnings;
use strict;

use XML::LibXML;

my $xml = 'XML::LibXML'->load_xml(location => 'a.xml') ;

for my $url ($xml->findnodes('//FileSpec/@URL')) {
    my $value = $url->getValue;
    $value =~ s{c://mine/testfiles}{d://yours};
    $url->setValue($value);
}

$xml->toFile('new.xml');

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