Android中的XPath没有产生java结果

1 月 Questions & Answers 57

我试图使用下面的代码获得XPATH的结果。不管我使用的实际XPATH表达式是什么，我总是得不到任何结果

factory.setNamespaceAware(true);

DocumentBuilder builder = null;

builder = factory.newDocumentBuilder();
doc = builder.parse(getResources().openRawResource(R.raw.cdatest02));


NodeList nodes;
String exp = "//versionNumber";  

XPathFactory xfactory = XPathFactory.newInstance();
XPath xpath = xfactory.newXPath();

xpath.setNamespaceContext(new NamespaceContext() {
    public String getNamespaceURI(String s) {
        if (s.equals(XMLConstants.DEFAULT_NS_PREFIX))
            return doc.lookupNamespaceURI(null);
        else
            return doc.lookupNamespaceURI(s);
    }

    public String getPrefix(String s) {
        return doc.lookupPrefix(s);
    }

    public Iterator getPrefixes(String s) {
        return null;
    }
});


nodes = (NodeList) xpath.evaluate(exp, doc,XPathConstants.NODESET);
Log.i("xpath results", "nothing returned");

我怀疑这个问题与XML的名称空间有关。XML声明了一个默认名称空间

XML是这样开始的（非常截断）

<?xml version="1.0" encoding="UTF-8"?>
<ClinicalDocument xmlns="urn:hl7-org:v3" xmlns:npfitlc="NPFIT:HL7:Localisation" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"  classCode="DOCCLIN" moodCode="EVN">
    <typeId root="2.16.840.1.113883.1.3" extension="POCD_HD000040"/>
    <npfitlc:messageType root="2.16.840.1.113883.2.1.3.2.4.18.17" extension="POCD_MT000012GB01"/>/
    <id root="A709A442-3CF4-476E-8377-376500E829C9"/>
    <code code="1234567" codeSystem="2.16.840.1.113883.2.1.3.2.4.15"/>
    <title mediaType="text/plain" representation="TXT">Patient Health Record Summary</title>
    <effectiveTime value="201305192000+01"/>
    <confidentialityCode code="V" displayName="very restricted" codeSystem="2.16.840.1.113883.5.25"/>
    <setId root="411910CF-1A76-4330-98FE-C345DDEE5553"/>
    <versionNumber value="1"/>
    .... lots more lines of XML ...,

你觉得我哪里出了问题吗

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Android中的XPath没有产生java结果

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