Java - convert xml object to String

Question

So I am pulling out specific tags and elements from an xml document using xPath and storing it in an object. My question is how can I convert this object to a string. I have tried the .toString() method, but all that it give me is the following:

LocalHost test: org.apache.xml.dtm.ref.DTMNodeList@717e717e

my code is below:

DocumentBuilderFactory domFactory = DocumentBuilderFactory.newInstance();
            domFactory.setNamespaceAware(true); // never forget this!
            DocumentBuilder builder = domFactory.newDocumentBuilder();
            org.w3c.dom.Document doc =  builder.parse("src/webSphere/testcases/positiveCode-data.xml");

            XPathFactory factory = XPathFactory.newInstance();
            XPath xpath = factory.newXPath();
            XPathExpression expr 
             = xpath.compile(" /tests/class/method/params[@name='config']/param/text()");
            MQQueueConnectionFactory cf = new MQQueueConnectionFactory();
            Object result = expr.evaluate(doc, XPathConstants.NODESET);


            System.out.println("LocalHost test: " + result.toString());

here is my xml file:

<?xml version ="1.0" encoding = "UTF-8"?>
<tests xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:noNamespaceSchemaLocation="http://jtestcase.sourceforge.net/dtd/jtestcase2.xsd">
    <class name="Success">
        <method name="success">
            <test-case name="positive-code">
                <params name="config">
                    <param name="hostName" type="java.lang.String">localhost</param>
                    <param name="port" type="int">7080</param>
                    <param name="transportType" type="java.lang.String">10</param>
                    <param name="queueManager" type="java.lang.String">MB8QMGR</param>
                    <param name="channel" type="java.lang.String">10</param>
                    <param name="inputQueue" type="java.lang.String">10</param>
                    <param name="outputQueue" type="java.lang.String">20</param>
                    <param name="testFile" type="java.lang.String">+</param>
                    <param name="expectedResultFile" type="java.lang.String">+</param>
                </params>
                <asserts>
                    <assert name="result" type="int" action="EQUALS">
                        30
                </assert>
                </asserts>
            </test-case>


        </method>
    </class>
</tests>

You need to override the toString method of the Object you want to get printed in Readable way, otherwise you will get the Object reference value using toString — RaceBase
– RaceBase, Commented Jul 24, 2013 at 8:25
It seems that DTMNodeList does not override Objects toString(). So you have to handle the Type DTMNodeList explicitly. Are you sure it's always this type? — boskop
– boskop, Commented Jul 24, 2013 at 8:31

Petr Janeček · Accepted Answer · 2013-07-24 08:48:35Z

2

Sure. You can see that you have an instance of a NodeList.

You can get the length of the list and then all Node items at a specific indexes and print them out based on what you expect of them - most likely their text content, so Node#getTextContent() (or anything other you want to print out - node name, node type etc.) in a loop.

NodeList resultList = (NodeList)expr.evaluate(doc, XPathConstants.NODESET);
int listLength = resultList.getLength();
for (int i = 0; i < listLength; i++) {
    System.out.println("LocalHost test (" + i + "): " + resultList.item(i).getTextContent());
}

EDIT

If you expect a single String value simply do

String resultList = (String)expr.evaluate(doc, XPathConstants.STRING);

This will convert the result to a String following the XPath String conversion rules.

edited Jul 24, 2013 at 8:48

answered Jul 24, 2013 at 8:29

Petr Janeček

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5 Comments

James King Over a year ago

Its not resolving DTMNNodeList as a type, do I have to import this or add a jar somewhere?

Petr Janeček Over a year ago

It is. You specified that it will return a NodeList when you executed expr.evaluate(doc, XPathConstants.NODESET). If you expected a single String and not a list of text nodes, you might have wanted to use expr.evaluate(doc, XPathConstants.STRING). Anyway, you will have to manually write a cast there (which will be safe).

James King Over a year ago

I just seem to get a null or blank. im using the following line just to see if Im getting one: String result = (String) expr.evaluate(doc, XPathConstants.STRING); but with no luck. What am I doing wrong?

Petr Janeček Over a year ago

@AndrewMurphy Your XPath expresion is wrong. You forgot to add a location step for <test-case name="positive-code">. Anyway, you will get a NodeList of String values, so I recommend the first approach from my solution.

James King Over a year ago

yea just saw that now. Such an idiot and not enough coffee. Thank you very much Slanec, a gentleman and a scholar

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