PHP 中的 simpleXML 从 XML 文档中的嵌套命名空间读取元素

我被难住了。我的文件中有以下 XML：

<?xml version="1.0" encoding="UTF-8"?>
<grant:GrantApplication xmlns:grant="http://apply.grants.gov/system/MetaGrantApplication" xmlns:globLib="http://apply.grants.gov/system/GlobalLibrary-V1.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://apply.grants.gov/system/MetaGrantApplication http://apply07.grants.gov/apply/opportunities/schemas/agency/oppEPA-R5-GL2011-1-cfda66.469.xsd">
    <grant:Forms>
        <EPA_KeyContacts:KeyContactPersons xmlns:EPA_KeyContacts="http://apply.grants.gov/forms/EPA_KeyContacts-V1.1" EPA_KeyContacts:FormVersion="1.1">
            <EPA_KeyContacts:AuthorizedRepresentative>
                <globLib:Name xmlns:globLib="http://apply.grants.gov/system/GlobalLibrary-V2.0">
                    <globLib:FirstName>Jane</globLib:FirstName>
                    <globLib:LastName>Doe</globLib:LastName>
                </globLib:Name>
            </EPA_KeyContacts:AuthorizedRepresentative>
        </EPA_KeyContacts:KeyContactPersons>
        <EPA4700_4_2_0:EPA4700_4_2_0 xmlns:EPA4700_4_2_0="http://apply.grants.gov/forms/EPA4700_4_2_0-V2.0" EPA4700_4_2_0:FormVersion="2.0">
            <EPA4700_4_2_0:ApplicantInfo>
                <EPA4700_4_2_0:ApplicantName>ABC 123</EPA4700_4_2_0:ApplicantName>
                <EPA4700_4_2_0:ApplicantAddress>
                    <EPA4700_4_2_0:Address>123 Street</EPA4700_4_2_0:Address>
                    <EPA4700_4_2_0:City>Buffalo</EPA4700_4_2_0:City>
                    <EPA4700_4_2_0:State>NY: New York</EPA4700_4_2_0:State>
                    <EPA4700_4_2_0:ZipCode>12345</EPA4700_4_2_0:ZipCode>
                </EPA4700_4_2_0:ApplicantAddress>
            <EPA4700_4_2_0:ApplicantInfo>
        <EPA4700_4_2_0:EPA4700_4_2_0 xmlns:EPA4700_4_2_0="http://apply.grants.gov/forms/EPA4700_4_2_0-V2.0" EPA4700_4_2_0:FormVersion="2.0">
        <SF424_2_1:SF424_2_1 xmlns:SF424_2_1="http://apply.grants.gov/forms/SF424_2_1-V2.1" SF424_2_1:FormVersion="2.1">
            <SF424_2_1:ContactPerson>
                <globLib:FirstName xmlns:globLib="http://apply.grants.gov/system/GlobalLibrary-V2.0">Jane</globLib:FirstName>
                <globLib:LastName xmlns:globLib="http://apply.grants.gov/system/GlobalLibrary-V2.0">Doe</globLib:LastName>
            <SF424_2_1:ContactPerson>
        <SF424_2_1:SF424_2_1>
    </grant:Forms>
</grant:GrantApplication>

在PHP中使用SimpleXML，我有以下代码：

$xml = simplexml_load_file($appdir);
$xml->registerXPathNamespace("grant","http://apply.grants.gov/system/MetaGrantApplication");
$xml->registerXPathNamespace("header","http://apply.grants.gov/system/Header-V1.0");
$xml->registerXPathNamespace("globLib","http://apply.grants.gov/system/GlobalLibrary-V2.0");
$xml->registerXPathNamespace("EPA_KeyContacts","http://apply.grants.gov/forms/EPA_KeyContacts-V1.1");
$xml->registerXPathNamespace("SF424A","http://apply.grants.gov/forms/SF424A-V1.0");
$xml->registerXPathNamespace("SF424_2_1","http://apply.grants.gov/forms/SF424_2_1-V2.1");
$xml->registerXPathNamespace("EPA4700_4_2_0","http://apply.grants.gov/forms/EPA4700_4_2_0-V2.0");
$rawContactFirstName = $xml->xpath("/grant:GrantApplication/grant:Forms/SF424_2_1:SF424_2_1/SF424_2_1:ContactPerson/globLib:FirstName");
$contactFirstName = $rawContactFirstName[0];
$rawContactLastName = $xml->xpath("/grant:GrantApplication/grant:Forms/EPA_KeyContacts:KeyContactPersons/EPA_KeyContacts:AuthorizedRepresentative/globLib:Name/globLib:LastName");
$contactLastName = $rawContactLastName[0];
$rawStreetAddress = $xml->xpath("/grant:GrantApplication/grant:Forms/EPA4700_4_2_0:EPA4700_4_2_0/EPA4700_4_2_0:ApplicantInfo/EPA4700_4_2_0:ApplicantAddress/EPA4700_4_2_0:Address");
$streetAddress = $rawStreetAddress[0];
$rawCity = $xml->xpath("/grant:GrantApplication/grant:Forms/EPA4700_4_2_0:EPA4700_4_2_0/EPA4700_4_2_0:ApplicantInfo/EPA4700_4_2_0:ApplicantAddress/EPA4700_4_2_0:City");
$city = $rawCity[0];
$rawState = $xml->xpath("/grant:GrantApplication/grant:Forms/EPA4700_4_2_0:EPA4700_4_2_0/EPA4700_4_2_0:ApplicantInfo/EPA4700_4_2_0:ApplicantAddress/EPA4700_4_2_0:State");
$state = $rawState[0];
$rawZip = $xml->xpath("/grant:GrantApplication/grant:Forms/EPA4700_4_2_0:EPA4700_4_2_0/EPA4700_4_2_0:ApplicantInfo/EPA4700_4_2_0:ApplicantAddress/EPA4700_4_2_0:ZipCode");
$zip = $rawZip[0];
echo $contactFirstName."<br>".
     $contactLastName."<br>".
     $streetAddress."<br>".
     $city."<br>".
     $state."<br>".
     $zip."<br>";

我得到以下输出：

注意：未定义的偏移量：0 在文件中.php在第 105 行 注意：未定义偏移量：0 在文件中.php在第 108 行

123街

水牛

纽约：纽约

12345

第 105 行引用 $rawContactFirstName[0] 和第 108 行引用 $rawContactLastName[0]

名字和姓氏在文档中出现了两次，由于引用 globLib 命名空间的方式不同，我引用了第一次出现的姓氏和第二次出现的名字。

我无法使用 globLib 命名空间从任何元素中获取任何信息，我不明白为什么。我可以从文档中获取任何其他信息，只要它不使用 globLib 命名空间。

$xml->xpath((; 应该返回一个数组。请考虑以下事项：

print_r($rawContactFirstName);

输出：阵列 ( (

var_dump($rawContactFirstName);
var_dump($rawContactFirstName[0]);

输出：array(0( { }

我不明白所有其他命名空间如何毫无问题地返回数据，除了这个使用完全相同的技术。根据 http://validator.w3.org/XML文档是有效的。

有什么想法吗？