相关疑难解决方法(0)

我正在尝试使用XPath查询选择一个节点,我不明白为什么XML :: LibXML在有xmlns属性时找不到该节点.这是一个演示此问题的脚本:

#!/usr/bin/perl

use XML::LibXML; # 1.70 on libxml2 from libxml2-dev 2.6.16-7sarge1 (don't ask)
use XML::XPath;  # 1.13
use strict;
use warnings;

use v5.8.4; # don't ask

my ($xpath, $libxml, $use_namespace) = @ARGV;

my $xml = sprintf(<<'END_XML', ($use_namespace ? 'xmlns="http://www.w3.org/2000/xmlns/"' : q{}));
<?xml version="1.0" encoding="iso-8859-1"?>
<RootElement>
  <MyContainer %s>
    <MyField>
        <Name>ID</Name>
        <Value>12345</Value>
    </MyField>
    <MyField>
        <Name>Name</Name>
        <Value>Ben</Value>
    </MyField>
  </MyContainer>
</RootElement>
END_XML

my $xml_parser
    = $libxml ? XML::LibXML->load_xml(string => $xml, keep_blanks => 1)
    :           XML::XPath->new(xml => $xml);

my $nodecount = 0;
foreach …