Java XML parsing

Question

I need to extract (using Java) the tag for the given name tag from XML file like this:

Here is my XML file:

<aa>
  <bb>
    <name>k1</name>
    <value>5</value>
  </bb>
  <bb>
    <name>k2</name>
    <value>7</value>
 </bb>
</aa>

Input to function: full path to <name> tag, e.g.: /aa/bb/name=k2
( Output for this example should return 7)

Also more advanced question: I need to extract all name:value pairs from the XML file then the name is given by regular expression I am thinking that XPath is the right tool here, but devil in details.

Did you have a question? (And by that I mean a specific question.) — Andrew Thompson
– Andrew Thompson, Commented Apr 19, 2011 at 3:09
I think you have three questions here. 1. To get the value 7 ie the value of value_tag_start inside the second bb_tag_start. 2. To get all the name value pairs ie tag name and the value. 3. If the tag name is given as regular expression get the value. Please clarify — Ammu
– Ammu, Commented Apr 19, 2011 at 3:25
To: Andrew Thompson. I have question 1 and 3 from your list. Thanks! — user607573
– user607573, Commented Apr 19, 2011 at 4:08
Lots and lots of duplicates. Here's one stackoverflow.com/questions/23106/… (this is linked to the second result in search) — Anon
– Anon, Commented Apr 19, 2011 at 12:54

bdoughan · Accepted Answer · 2011-04-19 12:47:22Z

2

You can use the javax.xml.xpath APIs that are included as part of Java SE 5:

import java.io.FileReader;

import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathExpression;
import javax.xml.xpath.XPathFactory;

import org.xml.sax.InputSource;

public class Demo {

    public static void main(String[] args) throws Exception {
        XPathFactory xpf = XPathFactory.newInstance();
        XPath xpath = xpf.newXPath();
        XPathExpression xpe = xpath.compile("//bb[name/text()='k2']/value");

        InputSource xml = new InputSource(new FileReader("input.xml"));
        String result = xpe.evaluate(xml);
        System.out.println(result);
    }
}

answered Apr 19, 2011 at 12:47

bdoughan

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Comments

yegor256 · Accepted Answer · 2014-04-24 13:46:46Z

0

Try jcabi-xml (see this blog post) with a one-liner:

String found = new XMLDocument(text).xpath("/aa/bb[name='k2']/text()").get(0);

answered Apr 24, 2014 at 13:46

yegor256

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Aliya · Accepted Answer · 2016-03-23 21:37:42Z

import org.jdom.Document;
import org.jdom.Element;
import org.jdom.JDOMException;
import org.jdom.input.SAXBuilder;
import org.jdom.xpath.XPath;
import org.junit.Test;

import static org.junit.Assert.*;

import java.io.File;
import java.io.IOException;

import javax.xml.xpath.XPathExpressionException;

public class XmlParsingTest {
    @Test
    public void testParsing() throws XPathExpressionException, JDOMException, IOException {

         SAXBuilder builder = new SAXBuilder();
         File xmlFile = new File("src/test/resources/yourXMLDoc.xml");

         Document origDoc = (Document) builder.build(xmlFile);

         XPath xPathMonsOccCategoryIdInOriginalDoc = XPath.newInstance("//bb[name/text()='k2']/value");

         Element element = (Element) xPathMonsOccCategoryIdInOriginalDoc.selectSingleNode(origDoc.getRootElement());

         assertEquals("7", element.getTextTrim());


}

}

vtd-xml-author · Accepted Answer · 2016-03-23 23:10:39Z

0

Below is the code of extracting value using vtd-xml.

import com.ximpleware.*;

public class extractValue{
    public static void  main(String s[]) throws VTDException, IOException{
        VTDGen vg = new VTDGen();
        if (!vg.parseFile("input.xml", false));
        VTDNav vn = vg.getNav();
        AutoPilot ap = new AutoPilot(vn);
        ap.selectXPath("/aa/bb[name='k1']/value");
        int i=0;
        while ((i=ap.evalXPath())!=-1){
            System.out.println(" value ===>"+vn.toString(i));
        }   
    }
}

answered Mar 23, 2016 at 23:10

vtd-xml-author

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