Question

我对如何从xpath查询中提取数据感到困惑。我使用的是PHP 5.5.6，我得到了这个结果：

I'm all the countries:
DOMNodeList Object
(
    [length] => 0
)
1
I'm all the countries:
DOMNodeList Object
(
    [length] => 0
)
1
I'm all the countries:
DOMNodeList Object
(
    [length] => 0
)
1
I'm all the countries:
DOMNodeList Object
(
    [length] => 0
)
1

我的XML文件被截断（仅显示第一部分，我正在尝试使用大型XML文件）：

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<Data>
    <NewDataSet>
        <Table>
            <Country>Philippines</Country>
            <City>Subic Bay Weather Station</City>
        </Table>
        <Table>
            <Country>Philippines</Country>
            <City>Laoag</City>
        </Table>
        <Table>
            <Country>Philippines</Country>
            <City>Ninoy Aquino Inter-National Airport</City>
        </Table>
        <Table>
            <Country>Philippines</Country>
            <City>Davao Airport</City>
        </Table>
        <Table>
            <Country>Philippines</Country>
            <City>Clark Ab</City>
        </Table>
        <Table>
            <Country>Philippines</Country>
            <City>Legaspi</City>
        </Table>
        <Table>
            <Country>Philippines</Country>
            <City>Romblon</City>
        </Table>

我想要做的就是通过xpath查询显示Country标签内的内容。我的代码是：

<?php

    $reader = new XMLReader();
    $reader->open("countries.xml", "UTF-8");

    while($reader->read()){
        //echo var_dump($reader->nodeType), "<br/>";
        if($reader->nodeType == XMLReader::ELEMENT && $reader->localName == "Table"){
            $node = $reader->expand();
            $dom = new DOMDocument;
            $xp = new DomXPath($dom);
            $xp1 = $xp->query("//Country");
            echo "I'm all the countries: <pre>",print_r($xp1),"</pre>";

        }

    }

    $reader->close();


?>

我不明白为什么我没有获得$ xp1的价值，我只能使用$xp1->nodeValue或$xp1->item(0)->nodeValue。我确实尝试过，即使返回的对象只有＆＃34;长度＆＃34;回馈。我正在查看this site上的示例清单5，看起来我应该能够做到这一点。我错过了什么？

Answer 1

您的DOM为空，您永远不会向其添加$node。尝试：

$reader = new XMLReader();
$reader->open("countries.xml", "UTF-8");

while($reader->read()){
    if($reader->nodeType == XMLReader::ELEMENT && $reader->localName == "Table"){
        $node = $reader->expand();
        $dom = new DOMDocument;
        $n = $dom->importNode($node, true);
        $dom->appendChild($n);
        $xp = new DomXPath($dom);
        $xp1 = $xp->query("//Country");
        echo "I'm all the countries: <pre>{$xp1->item(0)->nodeValue}</pre>";

    }

}

$reader->close();

如何在php中获取xpath查询的结果？

1 个答案: