How to select all attribute values from a particular attribute using xpath in Java

Question

I have the following XML file containing GPS co-ordinates, and I was just wondering how I can extract the track latitudes and longitudes using Xpath in Java. So far I tried:

System.out.println(xpath.evaluate("/gpx/trk/trkseg/trkpt/@lat", doc));

but this only retrieves the first value? Please can someone tell me how to retrieve all the values in one go.

Many Thanks in advance.

<gpx xmlns="http://www.topografix.com/GPX/1/1"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" creator="MapSource 6.11.3"
version="1.1" xsi:schemaLocation="http://www.topografix.com/GPX/1/1
http://www.topografix.com/GPX/1/1/gpx.xsd">
<metadata>...</metadata>
<wpt lat="40.653792" lon="-111.922379">...</wpt>
<wpt lat="40.658111" lon="-111.919564">...</wpt>
<wpt lat="40.659546" lon="-111.917527">...</wpt>
<wpt lat="40.595857" lon="-111.910294">...</wpt>
<wpt lat="40.657349" lon="-111.918721">...</wpt>
<trk>
<name>FromParking</name>
<extensions>...</extensions>
<trkseg>
<trkpt lat="40.653782" lon="-111.922365">
    <ele>1224.376221</ele>
    <time>2009-11-19T20:00:11Z</time>
</trkpt>
<trkpt lat="40.653786" lon="-111.922350">
    <ele>1223.895508</ele>
    <time>2009-11-19T20:00:13Z</time>
</trkpt>
<trkpt lat="40.654449" lon="-111.922073">
    <ele>1224.376221</ele>
    <time>2009-11-19T20:00:22Z</time>
</trkpt>
<trkpt lat="40.654509" lon="-111.921919">
    <ele>1224.376221</ele>
    <time>2009-11-19T20:00:25Z</time>
</trkpt>
<trkpt lat="40.654618" lon="-111.921700">
    <ele>1224.856934</ele>
    <time>2009-11-19T20:00:35Z</time>
</trkpt>

What XML/XPath library are you using?

user1907906
– user1907906

2014-03-05 12:30:46 +00:00
Commented Mar 5, 2014 at 12:30 — user1907906
– user1907906, Commented Mar 5, 2014 at 12:30

Community · Accepted Answer · 2017-05-23 12:03:41Z

1

Aside from the namespaces issue I described in my answer to your previous question, your fundamental problem here is that the XPath.evaluate methods without a QName returnType parameter will evaluate the XPath expression as a string, and the XPath rules say that the string value of a node set containing more than one node is defined to be the string value of the first node in the set in document order.

If you want to evaluate XPath expressions that return a set of nodes then you must use one of the XPath methods that takes a QName, pass XPathConstants.NODESET as the requested return type, and cast the result returned from evaluate to a org.w3c.dom.NodeList which you can then iterate over.

edited May 23, 2017 at 12:03

CommunityBot

11 silver badge

answered Mar 5, 2014 at 12:46

Ian Roberts

123k17 gold badges177 silver badges191 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Omoro · Accepted Answer · 2014-03-05 12:38:18Z

0

Try this: to retrieve all trkpt attributes do this:

String trkpt ="/gpx/trk/trkseg/trkpt";
NodeList nodeList= (NodeList) xpath.compile(trkpt).evaluate(doc, XPathConstants.NODESET);

for(int i=0; i<nodeList.getLength(); i++){
   Node node = nodeList.item(i);
   NamedNodeMap attributesMap = node.getAttributes();

   for (int j = 0; j< attributesMap.getLength(); j++) {            
     Node attributeNode = attributesMap.item(j);       
     String attributeName = attributeNode.getNodeName();        
     String attributeValue = attributeNode.getNodeValue();

     System.out.println(attributeName + "=" + attributeValue);
   }
}

edited Mar 5, 2014 at 12:38

answered Mar 5, 2014 at 12:33

Omoro

97211 silver badges22 bronze badges

Collectives™ on Stack Overflow

How to select all attribute values from a particular attribute using xpath in Java

2 Answers 2

Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related