count xml nodes under specific node
<element>
<slot name="slot1">
<port status="active"/>
<port status="i开发者_如何学Cnactive"/>
</slot>
<slot name="slot2">
<port status="active"/>
</slot>
</element>
NodeList listOfElement = doc.getElementsByTagName("port");
this gives total number of port in xml file.
I need to find out how many ports are under slot1.
One way is to use xpath to filter out the resulting list:
XPath xpath = XPathFactory.newInstance().newXPath();
NodeList list=(NodeList) xpath.evaluate("/element/slot[@name='slot1']/port",doc, XPathConstants.NODESET);
This will only count the ports that are under slot with name 'slot1'
.
You could use the javax.xml.xpath
libraries in Java SE, and leverage the count
function:
import java.io.FileInputStream;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathFactory;
import org.xml.sax.InputSource;
public class Demo {
public static void main(String[] args) throws Exception {
XPath xp = XPathFactory.newInstance().newXPath();
InputSource xml = new InputSource(new FileInputStream("input.xml"));
double count = (Double) xp.evaluate("count(//slot[@name='slot1']/port)", xml, XPathConstants.NUMBER);
}
}
what about this?
var slot1 = doc.getElementsByName("slot1");
var slot1_count = slot1[0].getElementsByTagName("port").length;
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