Member Avatar for michael.ngobeni

Hi guys

I have a tricky XML/Java situation that I need some tips on
I have an XML file
<country>
<country-name code=”USA”>
<city>City1</city>
<city>City2</city>
<city>City3</city>
</country-name>

<country-name code=”FRA”>
<city>City1</city>
<city>City2</city>
<city>City3</city>
</country-name>

</country >

Firstly I need to count how many cities per country. I know I have to get the parent and child nodes and so on
Secondly I need to display these cities names per country (if code =”FRA”)'

How do I do this in Java?
Thanks in advance!

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  • Latest Post Latest Post by orko

Dani AI

Generated

Good starting points from and — they pointed you toward XML tooling. Two concise, practical ways to solve both parts of your task follow: (A) bind the XML to Java objects and iterate to count/list cities, or (B) run an XPath query to count or select city nodes directly. Both are simple to apply; below are minimal examples and a few gotchas to watch for.

Example: bind with JAXB (POJOs)

@XmlRootElement(name="country")
public class Countries {
  @XmlElement(name="country-name")
  private List<CountryName> countryName;
  // getters/setters
}

public class CountryName {
  @XmlAttribute(name="code")
  private String code;
  @XmlElement(name="city")
  private List<String> city;
  // getters/setters
}

// unmarshal + use
JAXBContext jc = JAXBContext.newInstance(Countries.class);
Countries countries = (Countries) jc.createUnmarshaller().unmarshal(new File("countries.xml"));

for (CountryName cn : countries.getCountryName()) {
  System.out.println(cn.getCode() + " -> " + cn.getCity().size()); // count per country
}

countries.getCountryName().stream()
  .filter(cn -> "FRA".equals(cn.getCode()))
  .findFirst()
  .ifPresent(cn -> cn.getCity().forEach(System.out::println)); // list for code="FRA"

Alternative: XPath (no binding)

XPath xp = XPathFactory.newInstance().newXPath();
Double count = (Double) xp.evaluate("count(/country/country-name[@code='FRA']/city)", doc, XPathConstants.NUMBER);

NodeList nodes = (NodeList) xp.evaluate("/country/country-name[@code='FRA']/city", doc, XPathConstants.NODESET);
for (int i=0;i<nodes.getLength();i++) System.out.println(nodes.item(i).getTextContent());

Notes and quick troubleshooting

  • Make sure the XML is well formed (use straight ASCII quotes for attributes).
  • Hyphenated element names like country-name require explicit name mapping in annotations (see @XmlElement(name="country-name")).
  • If the app runs on Java 11 or newer, JAXB classes are no longer bundled in the JDK — add the JAXB API and an implementation (for example jakarta.xml.bind:jakarta.xml.bind-api plus a runtime like com.sun.xml.bind:jaxb-impl or org.glassfish.jaxb:jaxb-runtime). (openjdk.org)

Either approach will let you produce the per-country counts and lists quickly; choose binding if you prefer typed objects, or XPath if you want a compact query-based solution.

Recommended Answers

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Member Avatar for darkagn

Hi michael.ngobeni,

Have a read of the javax.xml classes in the Java API. You should look in particular at the parsers package. Another step might be the java xml tutorials on sun.com.

Anyway I hope this has given you a starting point. Post back if you need more help.

Cheers
darkagn

Member Avatar for orko

yah... java's xml parsers can help you more... couple of them r, DOM, JDOM, SAX...
if u use DOM or JDOM, get the whole document parsed, then just use a method called getElementsByTagName(String Tag). This is pretty easy to do. you will have to follow factory pattern.

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