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NSXMLDocument,带有名称空间的nodesForXPath

nsxmldocument namespaces xpath cocoa

4

Vegar · 技术社区 · 14 年前

我想从xml文件中获取一组元素,但是一旦这些元素涉及到名称空间,就失败了。

这是xml文件的一个片段:

<gpx xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
     xmlns:xsd="http://www.w3.org/2001/XMLSchema" 
     version="1.0" creator="Groundspeak Pocket Query"
     xsi:schemaLocation="http://www.topografix.com/GPX/1/0 http://www.topografix.com/GPX/1/0/gpx.xsd http://www.groundspeak.com/cache/1/0 http://www.groundspeak.com/cache/1/0/cache.xsd" 
     xmlns="http://www.topografix.com/GPX/1/0"> 
  <name>My Finds Pocket Query</name>   
  <desc>Geocache file generated by Groundspeak</desc>   
  <author>Groundspeak</author>   
  <email>contact@groundspeak.com</email> 
  <time>2010-09-15T16:18:55.9846906Z</time> 
  <keywords>cache, geocache, groundspeak</keywords>   
  <bounds minlat="41.89687" minlon="5.561883" maxlat="70.669967" maxlon="25.74735" />    
  <wpt lat="62.244933" lon="25.74735">
    <time>2010-01-11T08:00:00Z</time>
    <name>GC22W1T</name>
    <desc>Kadonneet ja karanneet by ooti, Traditional Cache (1.5/2)</desc>
    <url>http://www.geocaching.com/seek/cache_details.aspx?guid=4af28fe9-401b-44df-b058-5fd5399fc083</url>
    <urlname>Kadonneet ja karanneet</urlname>
    <sym>Geocache Found</sym>
    <type>Geocache|Traditional Cache</type>
    <groundspeak:cache id="1521507" available="True" archived="False" xmlns:groundspeak="http://www.groundspeak.com/cache/1/0">
      <groundspeak:name>Kadonneet ja karanneet</groundspeak:name>
      <groundspeak:placed_by>ooti</groundspeak:placed_by>
      <groundspeak:owner id="816431">ooti</groundspeak:owner>
      <groundspeak:type>Traditional Cache</groundspeak:type>
      <groundspeak:container>Small</groundspeak:container>
      <groundspeak:difficulty>1.5</groundspeak:difficulty>
      <groundspeak:terrain>2</groundspeak:terrain>
      <groundspeak:country>Finland</groundspeak:country>
      <groundspeak:state>
      </groundspeak:state>
      <groundspeak:short_description html="True">
      </groundspeak:short_description>
      <groundspeak:encoded_hints>
      </groundspeak:encoded_hints>
      <groundspeak:travelbugs />
    </groundspeak:cache>   
  </wpt>
</gpx>

grounspeak:cache //groundspeak:cache 也不是 //cache 好像什么都没还。

NSArray *caches = [self.xml nodesForXPath:@"//cache" error:&error];

有什么线索吗?

3 回复 | 直到 14 年前

1

5

user357812 user357812 14 年前

这个 //cache 指:

你的 groundspeak:cache 元素位于命名空间URI下 http://www.groundspeak.com/cache/1/0

因此,如果不能声明名称空间前缀绑定(我认为不能使用cocoa…),可以使用以下XPath表达式:

//*[namespace-uri()='http://www.groundspeak.com/cache/1/0' and
    local-name()='cache']

如果你不想对命名空间这么严格。。。

//*[local-name()='cache']

,因为最终可能会选择错误的节点,而且在处理XML时,您的工具应该支持名称空间。

<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
    <xsl:template match="/">
            <xsl:copy-of select="//*[namespace-uri() =
                                     'http://www.groundspeak.com/cache/1/0' and
                                     local-name() = 'cache']"/>
    </xsl:template>
</xsl:stylesheet>

输出:

<groundspeak:cache id="1521507" available="True" archived="False"
            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
            xmlns:xsd="http://www.w3.org/2001/XMLSchema"
            xmlns="http://www.topografix.com/GPX/1/0"
            xmlns:groundspeak="http://www.groundspeak.com/cache/1/0">
    <groundspeak:name>Kadonneet ja karanneet</groundspeak:name>
    <groundspeak:placed_by>ooti</groundspeak:placed_by>
    <groundspeak:owner id="816431">ooti</groundspeak:owner>
    <groundspeak:type>Traditional Cache</groundspeak:type>
    <groundspeak:container>Small</groundspeak:container>
    <groundspeak:difficulty>1.5</groundspeak:difficulty>
    <groundspeak:terrain>2</groundspeak:terrain>
    <groundspeak:country>Finland</groundspeak:country>
    <groundspeak:state></groundspeak:state>
    <groundspeak:short_description html="True"></groundspeak:short_description>
    <groundspeak:encoded_hints></groundspeak:encoded_hints>
    <groundspeak:travelbugs />
</groundspeak:cache>

2

1

Amy Worrall 13 年前

您需要向文档的根节点添加新的namespace属性,定义查询子节点时可以使用的前缀:

NSXMLDocument *xmldoc = ...
NSXMLElement *namespace = [NSXMLElement namespaceWithName:@"mns" stringValue:@"http://mynamespaceurl.com/mynamespace"];
[xmldoc.rootElement addNamespace:namespace];

NSArray * caches = [xmldoc.rootElement nodesForXPath:@"//mns:caches" error:&error];

3

0

abdollar 14 年前

//gr公司缓存应该工作。您可能还需要一个名称空间uri设置