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PHP DOMXPath中的Xpath無法正常工作

[英]Xpath in PHP DOMXPath Not Working

 原文  2017-01-15 01:57:34  9   1    php/ xpath

問題描述

我無法使用以下DOMXpath： 

    $responseDOM = new DOMDocument();
    $responseDOM->loadXML($responsestring);
    $responseXPath = new DOMXpath($responseDOM);
    $responseXPath->registerNamespace("ns", "http://www.loc.gov/MARC21/slim");
    $xpatheval = $responseXPath->query('//record');
    d(get_class($xpatheval));
    d($xpatheval->length);

d（）是我使用的自定義庫函數，類似於var_dump。 當我轉儲$ xpatheval-> length時，當它應該大於0時，我得到0，因為$ xpatheval應該包含相關的XML元素。

這是$ responsestring： 

<searchRetrieveResponse xmlns="http://www.loc.gov/zing/srw/" xmlns:oclcterms="http://purl.org/oclc/terms/" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:diag="http://www.loc.gov/zing/srw/diagnostic/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<version>1.1</version>
<numberOfRecords>641</numberOfRecords>
<records>
<record>
<recordSchema>marcxml</recordSchema>
<recordPacking>xml</recordPacking>
<recordData>
<record xmlns="http://www.loc.gov/MARC21/slim">
    <leader>00000cam a2200000M  4500</leader>
    <controlfield tag="001">957956968</controlfield>
    <controlfield tag="008">160712s2016    gw      o     000 0 eng d</controlfield>
    <datafield ind1=" " ind2=" " tag="020">
      <subfield code="a">9783319415406</subfield>
      <subfield code="q">E-Book</subfield>
    </datafield>
    <datafield ind1=" " ind2=" " tag="020">
      <subfield code="a">3319415409</subfield>
    </datafield>
    <datafield ind1=" " ind2=" " tag="020">
      <subfield code="z">9783319415390</subfield>
    </datafield>
    <datafield ind1="0" ind2="0" tag="245">
      <subfield code="a">Computer Aided Verification :</subfield>
      <subfield code="b">28th International Conference, CAV 2016, Toronto, ON, Canada, July 17-23, 2016, Proceedings, Part II /</subfield>
      <subfield code="c">edited by Swarat Chaudhuri, Azadeh Farzan.</subfield>
    </datafield>
    <datafield ind1=" " ind2="1" tag="264">
      <subfield code="a">Cham</subfield>
      <subfield code="b">Springer International Publishing</subfield>
      <subfield code="c">2016</subfield>
    </datafield>
    <datafield ind1=" " ind2=" " tag="300">
      <subfield code="a">1 Online-Ressource.</subfield>
    </datafield>
    <datafield ind1="1" ind2=" " tag="490">
      <subfield code="a">Lecture Notes in Computer Science</subfield>
      <subfield code="v">9780</subfield>
    </datafield>
    <datafield ind1="0" ind2=" " tag="490">
      <subfield code="a">SpringerLink : Bücher</subfield>
    </datafield>
    <datafield ind1=" " ind2="0" tag="650">
      <subfield code="a">Computer science.</subfield>
    </datafield>
    <datafield ind1=" " ind2="0" tag="650">
      <subfield code="a">Computer organization.</subfield>
    </datafield>
    <datafield ind1=" " ind2="0" tag="650">
      <subfield code="a">Software engineering.</subfield>
    </datafield>
    <datafield ind1=" " ind2="0" tag="650">
      <subfield code="a">Computer logic.</subfield>
    </datafield>
    <datafield ind1=" " ind2="0" tag="650">
      <subfield code="a">Logic, Symbolic and mathematical.</subfield>
    </datafield>
    <datafield ind1=" " ind2="7" tag="650">
      <subfield code="a">Computer logic.</subfield>
      <subfield code="2">fast</subfield>
      <subfield code="0">(OCoLC)fst00872265</subfield>
    </datafield>
    <datafield ind1=" " ind2="7" tag="650">
      <subfield code="a">Computer organization.</subfield>
      <subfield code="2">fast</subfield>
      <subfield code="0">(OCoLC)fst00872356</subfield>
    </datafield>
    <datafield ind1=" " ind2="7" tag="650">
      <subfield code="a">Computer science.</subfield>
      <subfield code="2">fast</subfield>
      <subfield code="0">(OCoLC)fst00872451</subfield>
    </datafield>
    <datafield ind1=" " ind2="7" tag="650">
      <subfield code="a">Logic, Symbolic and mathematical.</subfield>
      <subfield code="2">fast</subfield>
      <subfield code="0">(OCoLC)fst01002068</subfield>
    </datafield>
    <datafield ind1=" " ind2="7" tag="650">
      <subfield code="a">Software engineering.</subfield>
      <subfield code="2">fast</subfield>
      <subfield code="0">(OCoLC)fst01124185</subfield>
    </datafield>
    <datafield ind1="1" ind2=" " tag="700">
      <subfield code="a">Chaudhuri, Swarat,</subfield>
      <subfield code="e">Herausgeber.</subfield>
      <subfield code="4">edt</subfield>
    </datafield>
    <datafield ind1="1" ind2=" " tag="700">
      <subfield code="a">Farzan, Azadeh,</subfield>
      <subfield code="e">Herausgeber.</subfield>
      <subfield code="4">edt</subfield>
    </datafield>
    <datafield ind1=" " ind2=" " tag="856">
      <subfield code="u">http://sfx.ethz.ch/sfx_locater?sid=ALEPH:EBI01&amp;genre=book&amp;isbn=9783319415406</subfield>
      <subfield code="z">Online via SFX</subfield>
    </datafield>
    <datafield ind1="4" ind2=" " tag="856">
      <subfield code="u">http://dx.doi.org/10.1007/978-3-319-41540-6</subfield>
      <subfield code="x">Verlag</subfield>
    </datafield>
  </record>
</recordData>
</record>
<record>
<recordSchema>marcxml</recordSchema>
<recordPacking>xml</recordPacking>
<recordData>
<record xmlns="http://www.loc.gov/MARC21/slim">
    <leader>00000cam a2200000Mi 4500</leader>
    <controlfield tag="001">932169433</controlfield>
    <controlfield tag="008">151012t20152015sz a    ob    101 0 eng d</controlfield>
    <datafield ind1=" " ind2=" " tag="020">
      <subfield code="a">9783319245409</subfield>
      <subfield code="q">electronic bk.</subfield>
    </datafield>
    <datafield ind1=" " ind2=" " tag="020">
      <subfield code="a">3319245406</subfield>
      <subfield code="q">electronic bk.</subfield>
    </datafield>
    <datafield ind1=" " ind2=" " tag="020">
      <subfield code="z">9783319245393</subfield>
    </datafield>
    <datafield ind1=" " ind2=" " tag="020">
      <subfield code="z">3319245392 (print)</subfield>
    </datafield>
    <datafield ind1=" " ind2=" " tag="020">
      <subfield code="z">9783319245393 (print)</subfield>
    </datafield>
    <datafield ind1="1" ind2="0" tag="245">
      <subfield code="a">Cognitive Radio Oriented Wireless Networks :</subfield>
      <subfield code="b">10th International Conference, CROWNCOM 2015, Doha, Qatar, April 21-23, 2015, revised selected papers /</subfield>
      <subfield code="c">edited by Mark Weichold, Mounir Hamdi, Muhammad Zeeshan Shakir, Mohamed Abdallah, George K. Karagiannidis, Muhammad Ismail.</subfield>
    </datafield>
    <datafield ind1=" " ind2="1" tag="264">
      <subfield code="a">Cham :</subfield>
      <subfield code="b">Springer,</subfield>
      <subfield code="c">2015.</subfield>
    </datafield>
    <datafield ind1=" " ind2="4" tag="264">
      <subfield code="c">©2015</subfield>
    </datafield>
    <datafield ind1=" " ind2=" " tag="300">
      <subfield code="a">1 online resource (xv, 805 pages) :</subfield>
      <subfield code="b">illustrations.</subfield>
    </datafield>
    <datafield ind1="1" ind2=" " tag="490">
      <subfield code="a">Lecture notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering,</subfield>
      <subfield code="x">1867-8211 ;</subfield>
      <subfield code="v">156</subfield>
    </datafield>
    <datafield ind1="0" ind2=" " tag="505">
      <subfield code="a">Dynamic Spectrum Access/Management -- Networking Protocols for CR -- Modeling and Theory -- HW Architecture and Implementations -- Next Generation of Cognitive Networks -- Standards and Business Models -- Emerging Applications for Cognitive Networks.</subfield>
    </datafield>
    <datafield ind1=" " ind2=" " tag="520">
      <subfield code="a">This book constitutes the thoroughly refereed post-conference proceedings of the 10th International Conference on Cognitive Radio Oriented Wireless Networks, CROWNCOM 2015, held in Doha, Qatar, in April 2015. The 66 revised full papers presented were carefully reviewed and selected from 110 submissions and cover the evolution of cognitive radio technology pertaining to 5G networks. The papers are clustered to topics on dynamic spectrum access/management, networking protocols for CR, modeling and theory, HW architecture and implementations, next generation of cognitive networks, standards and business models, and emerging applications for cognitive networks.</subfield>
    </datafield>
    <datafield ind1=" " ind2="0" tag="650">
      <subfield code="a">Cognitive radio networks</subfield>
      <subfield code="v">Congresses.</subfield>
    </datafield>
  </record>
</recordData>
</record>
<nextRecordPosition>201</nextRecordPosition>
<resultSetIdleTime/>
<echoedSearchRetrieveRequest xmlns:srw="http://www.loc.gov/zing/srw/">
<version>1.1</version>
<query>srw.su="Computer organization"</query>
<maximumRecords>100</maximumRecords>
<recordPacking>xml</recordPacking>
<startRecord>101</startRecord>
<sortKeys>relevance</sortKeys>
<wskey>7Rn7E7osoeJeQURAiEO4GH74HZa6BLdt7eXahgxdvwnfO6Ph7za1OzU9M2zx0e9nuDHVO34b5HfnLuOw</wskey>
</echoedSearchRetrieveRequest>
</searchRetrieveResponse>

我感覺問題的一部分來自兩個名稱空間中的<record>元素。 我正在嘗試在“ http://www.loc.gov/MARC21/slim ”命名空間中檢索一個。

我該如何解決這個問題？

1 個解決方案

解決方案1
 0  2017-01-15 02:53:11

您沒有在XPath中使用注冊的名稱空間前綴ns 。 如果不使用該前綴，則假定您要在空名稱空間中查找record元素，因此未找到結果（ $xpatheval->length值為0）： 

$responseXPath->registerNamespace("ns", "http://www.loc.gov/MARC21/slim");
$xpatheval = $responseXPath->query('//ns:record');
echo $xpatheval->length;

demo

輸出： 

2

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