Cannot work with XML file. InputStream is null

Question

What am I doing wrong here? I am getting the error there there is nothing in the input stream when that is not the case. The file is there and it is titled correctly. I want to grab the ip addresses i have put in my XML file. Is there a better way to parse in the file instead of dBuilder.parse(XMLReader.class.getResourceAsStream("C:\\Tools\\CLA\\test.xml")); ?

I am experiencing this exception:

Caused by: java.lang.IllegalArgumentException: InputStream cannot be null
    at javax.xml.parsers.DocumentBuilder.parse(Unknown Source)
    at com.Intel.ameier.XMLparser.TryXML(XMLparser.java:17)

Here is the code:

import java.io.IOException;
import org.xml.sax.*;
import org.w3c.dom.*;
import javax.xml.parsers.*;

public class XMLparser {

    protected void TryXML() throws ParserConfigurationException, SAXException, IOException{

        DocumentBuilderFactory builderFactory = DocumentBuilderFactory.newInstance();

        DocumentBuilder dBuilder = builderFactory.newDocumentBuilder();
        Document document = dBuilder.parse(XMLReader.class.getResourceAsStream("C:\\Tools\\test.xml"));
        document.normalize();

        NodeList rootNodes = document.getElementsByTagName("info");
        Node rootNode = rootNodes.item(0);
        Element rootElement = (Element)rootNode;
        NodeList compList = rootElement.getElementsByTagName("computer");
        for(int i = 0;i < compList.getLength(); i++){

            Node computer = compList.item(i);
            Element compElement = (Element)computer;

            Node theIP = compElement.getElementsByTagName("ipaddress").item(0);
            Element theIpElement = (Element)theIP;

            System.out.println("The comptuer ip is : " + theIpElement.getTextContent());


        }


    }


}

XML File:

<?xml version="1.0"?>
<info>
    <testsuite>
        <name></name>
    </testsuite>
    <computer>
        <ipaddress>111.11.11.6</ipaddress>
    </computer>
    <computer>
        <ipaddress>111.11.11.5</ipaddress>
    </computer>
    <computer>
        <ipaddress>111.11.11.3</ipaddress>
    </computer>
</info>

Jon Skeet · Accepted Answer · 2014-06-02 14:35:30Z

7

This has nothing to do with XML. You're using Class.getResourceAsStream, which is meant to get a resource to be loaded from the classpath for that class's class loader... but you're passing in a filename instead.

If you want to create an input stream for a file, just use FileInputStream:

Document document = dBuilder.parse(new FileInputStream("C:\\Tools\\test.xml"));

Or better, in order to close the stream:

Document document:

try (InputStream stream = new FileInputStream("C:\\Tools\\test.xml")) {
    document = dBuilder.parse(stream);
}

answered Jun 2, 2014 at 14:35

Jon Skeet

1.5m893 gold badges9.3k silver badges9.3k bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Ducksauce88 Over a year ago

Thanks. Youtube(where i was getting this info) is great for learning but it will only get you so far....

Gunnlaugur Over a year ago

Thx, just what I was looking for.

Dave · Accepted Answer · 2014-06-02 15:56:44Z

1

It indeed has nothing to do with XML and Jon's answer is satisfactory.

However, the explanation is inaccurate. One can use Class.getResourceAsStream to load arbitrary files. There are situations when Class.getResourceAsStream is the preferred way of loading resources.

The issue here is that Class.getResourceAsStream() interprets its parameter as relative to each path in the classpath, and does not understand the absolute path that was passed here. It can only "see" files that are in the classpath.

You can try adding C:\Tools\CLA to your classpath and then just use

getResourceAsStream("/test.xml");

edited Jun 2, 2014 at 15:56

answered Jun 2, 2014 at 15:28

Dave

1,8743 gold badges25 silver badges36 bronze badges

Collectives™ on Stack Overflow

Cannot work with XML file. InputStream is null

2 Answers 2

2 Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

2 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related