Empty Strings in Array list when using getTextContent()

Question

So I've been trying to collect all of the nodes Names along with their contents in pre-order. So I used a recursive method to get all of the Nodes from the XML file along with the Text. Problem is whenever I execute it I keep on getting empty strings in the ArrayList. The empty Strings are next to Academy, Faculty and Department since they got no text.

I've tried deleting empty strings and null from the ArrayList but didnt work does anyone know a way to solve this problem and thanks!

Here is the XML File:

<?xml version="1.0"?>
<Academy>
    <Faculty>
        <Department name= "Science">
            <Director>Kay Jordan</Director>
            <Don>ABC</Don>
        </Department>
    </Faculty>
</Academy>

And here is the Java Code:

import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.TransformerException;

import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;

public class Gen2 {

    static ArrayList<String> SLDP = new ArrayList<String>(0);

    public static void main(String[] args) throws SAXException, IOException,
                ParserConfigurationException, TransformerException {

        DocumentBuilderFactory docBuilderFactory = DocumentBuilderFactory
            .newInstance();
        DocumentBuilder docBuilder = docBuilderFactory.newDocumentBuilder();
        Document document = docBuilder.parse(new File("Test.xml"));
        doSomething(document.getDocumentElement());

        System.out.print("< ");
        SLDP.removeAll(Arrays.asList(null," "));
        for(int z =0; z<SLDP.size();z++){
            System.out.print(SLDP.get(z).toString()+ " ");
        }
        System.out.print(" >");
    }

    public static void doSomething(Node node) {
        // do something with the current node instead of System.out
        //System.out.println(node.getNodeName());
        SLDP.add(node.getNodeName());
        System.out.println(node.getFirstChild().getTextContent());
        SLDP.add(node.getFirstChild().getTextContent());

        NodeList nodeList = node.getChildNodes();
        for (int i = 0; i < nodeList.getLength(); i++) {
            Node currentNode = nodeList.item(i);
            if (currentNode.getNodeType() == Node.ELEMENT_NODE) {
                //calls this method for all the children which is Element
                doSomething(currentNode);
            }
        }
    }
}

I ran your code and it works accordingly without changing a line. — T.Gounelle
– T.Gounelle, Commented Feb 25, 2015 at 22:55
@AbbéRésina Well it does work im not saying it dosnt, but the problem is if you check your output ull see a line space between Academy and Faculty..etc that is because there is string there in the ArrayList that is being printed when calling system.out.print.. The out put should be like that: < Academy Faculty Department Director Kay Jordan Don ABC > with 1 space between each... I hope you got what i mean — TheUnknown
– TheUnknown, Commented Feb 25, 2015 at 23:18

T.Gounelle · Accepted Answer · 2015-02-25 23:53:21Z

2

Simple way : in doSomething() trim the node name and content :

SLDP.add(node.getNodeName().trim());       
//System.out.print(node.getFirstChild().getTextContent());
SLDP.add(node.getFirstChild().getTextContent().trim());

Less simple : add this to the DocumentBuilderFactory :

docBuilderFactory.setIgnoringElementContentWhitespace(true);
docBuilderFactory.setValidating(true);
docBuilderFactory.setSchema(...);

But you will need the schema of the xml file for the parser to be able to validate and remove un-needed white spaces. See the documentation here.

answered Feb 25, 2015 at 23:53

T.Gounelle

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2 Comments

TheUnknown Over a year ago

The problem is that i dont knw the schema

TheUnknown Over a year ago

did couple of edits on the code and used the Trim() and it worked ! thanks alot

Pawel Hawro · Accepted Answer · 2015-02-25 23:54:47Z

0

Each new line in XML is new TEXT_NODE in child list. So calling:

SLDP.add(node.getFirstChild().getTextContent());

will result in adding new line character to SLDP array list.

You can prevent this by properly configuring DocumentBuilderFactory:

docBuilderFactory.setIgnoringElementContentWhitespace(true);

answered Feb 25, 2015 at 23:54

Pawel Hawro

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