Clash Royale CLAN TAG

Parse XML document with DOM parser, with multiple elements for each tag

I need to parse a XML document wich has same tag names. I'm giving you a sample of this code to see what I want to do..

<SystemData>
<SystemName>xmlexample</SystemName>
<Schools>
<School>
<SchoolName>SCHOOL1</SchoolName>
<Classes>
<Class>
<ClassName>ACLASS</ClassName>
</Class>
</Classes>
<Classes>
<Class>
<ClassName>BCLASS</ClassName>
</Class>
</Classes>
</School>

<School>
<SchoolName>SCHOOL2</SchoolName>
<Classes>
<Class>
<ClassName>CCLASS</ClassName>
</Class>
</Classes>
</School>
</Schools>
</SystemData>


The result I want is:

SCHOOL1
ACLASS
BCLASS

SCHOOL2
CCLASS


I'm trying with for loops but it gets me for every school all the classes..

My code so far:

NodeList schoolist = doc.getElementsByTagName("School");
int num = schoolist.getLength();

for (int temp = 0; temp < num; temp++) {
Node nNode = schoolist.item(temp);
if (nNode.getNodeType() == Node.ELEMENT_NODE) {
Element eElement = (Element) schoolist.item(temp);
Node schoolname = eElement.getFirstChild();

System.out.println("schoolname: " + eElement.getElementsByTagName("ClassName").item(0).getTextContent());
}

NodeList Classlist = doc.getElementsByTagName("Method");
int num1 = Classlist.getLength();

for (int i = 0; i < num1; i++) {

Node nNode1 = Classlist.item(i);

if (nNode1.getNodeType() == Node.ELEMENT_NODE) {
Element eElement1 = (Element) Classlist.item(i);
Node Classname = eElement1.getFirstChild();
System.out.println("Classname: " + eElement1.getElementsByTagName("ClassName").item(0).getTextContent());

}
}
}


This question has answers that may be good or bad; the system has marked it active so that they can be reviewed.

3 Answers
3

Some obvious problems with tag names:

System.out.println("schoolname: " + eElement.getElementsByTagName("ClassName").item(0).getTextContent());


should be

System.out.println("schoolname: " + eElement.getElementsByTagName("SchoolName").item(0).getTextContent());


and

NodeList Classlist = doc.getElementsByTagName("Method");


should be

NodeList Classlist = doc.getElementsByTagName("Class");


Then, you don't want to get all Class elements from the doc but all Class documents that are a child of the current school.

Class

Class

So finaly i managed to fix the code..This is how it works..

NodeList listOfSchool = doc.getElementsByTagName("School");


for(int s=0; s<listOfSchool.getLength() ; s++){


Node firstSchoolNode = listOfSchool.item(s);
if(firstSchoolNode .getNodeType() == Node.ELEMENT_NODE){


Element SchoolElement = (Element)firstSchoolNode ;

//-------
NodeList SchoolNameList = SchoolElement.getElementsByTagName("SchoolName");
Element SchoolNameElement = (Element)SchoolNameList .item(0);

NodeList textFNList = SchoolNameElement.getChildNodes();
System.out.println("School Name : " +
((Node)textFNList.item(0)).getNodeValue().trim());

//----

NodeList listOfSchoolNames = SchoolElement.getElementsByTagName("Class");

for(int i=0; i<listOfSchoolNames.getLength() ; i++){


Node firstClassNode = listOfSchoolNames.item(i);
if(firstClassNode .getNodeType() == Node.ELEMENT_NODE){

Element classElement = (Element)firstClassNode;
//----

NodeList ClassNameList = classElement .getElementsByTagName("ClassName");


Element ClassNameElement = (Element)ClassNameList.item(0);

NodeList textCLSNMList = ClassNameElement.getChildNodes();
System.out.println("class Name : " +
((Node)textCLSNMList .item(0)).getNodeValue().trim());

}
}


I would recommend using the javax.xml.xpath APIs in the Java SE 5 and above instead of getElementsByTagName to make your code more readable and easier to maintain.

javax.xml.xpath

getElementsByTagName

import javax.xml.xpath.*;
import org.w3c.dom.*;
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 schoolNameExpression = xPath.compile("SchoolName");
XPathExpression classNameExpression = xPath.compile("Classes/Class/ClassName");

InputSource inputSource = new InputSource("src/forum14671896/input.xml");
NodeList schoolNodes = (NodeList) xPath.evaluate("/SystemData/Schools/School", inputSource, XPathConstants.NODESET);
for(int x=0; x<schoolNodes.getLength(); x++) {
Node schoolElement = schoolNodes.item(x);

// School Name
System.out.print("School Name : ");
System.out.println(schoolNameExpression.evaluate(schoolElement, XPathConstants.STRING));

// Class Names
NodeList classNames = (NodeList) classNameExpression.evaluate(schoolElement, XPathConstants.NODESET);
for(int y=0; y<classNames.getLength(); y++) {
System.out.print("Class Name : ");
System.out.println(classNames.item(y).getTextContent());
}
System.out.println();
}
}

}


Output

School Name : SCHOOL1
Class Name : ACLASS
Class Name : BCLASS

School Name : SCHOOL2
Class Name : CCLASS


By clicking "Post Your Answer", you acknowledge that you have read our updated terms of service, privacy policy and cookie policy, and that your continued use of the website is subject to these policies.