AJAX ResponseXML coming back from a Servlet is null, but responseText has the XML

[sam jacksonville]

Hi All,
I am new to the ranch. I have been trying my best to resolve this issue but I am not able to figure out the issue. Here is what I am trying to do.

1.I have a landing page for my app called index.jsp.
2.I have a form with a text box named "cardname" with a submit button
3.When I click the submit button, an AJAX POST call is made to a Servlet which returns an XML that has the payment details for the selected card.
4.The responseText coming back to the AJAX call shows the XML, however when I try responseXML I am getting a null. Here is what I have checked to make sure before opening up this question:
a. I have made sure there XML structure is fine (I think I am doing it right )
b. I used the alert on the javascript to show the xml that came back on responseText, it was fine
c. I used alert to show the XML that came back on the responseXML, but I got [object XML] message.

5. I could not attach the code, but the responseXML is below. Thanks for reading my post.

Here is the XML that the servlet returns. The XML is generated using JAXB inside the servlet.

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<CardPayments>
<card>Amex</card>
<payments>
<payment>
<id>3</id>
<date>2012-09-06T00:00:00-04:00</date>
<amount>44.0</amount>
<cardType>Amex</cardType>
</payment>
<payment>
<id>4</id>
<date>2012-09-04T00:00:00-04:00</date>
<amount>12.0</amount>
<cardType>Amex</cardType>
</payment>
<payment>
<id>5</id>
<date>2012-09-04T00:00:00-04:00</date>
<amount>12.0</amount>
<cardType>Amex</cardType>
</payment>
<payment>
<id>6</id>
<date>2012-09-04T00:00:00-04:00</date>
<amount>12.0</amount>
<cardType>Amex</cardType>
</payment>
<payment>
<id>7</id>
<date>2012-09-05T00:00:00-04:00</date>
<amount>1.0</amount>
<cardType>Amex</cardType>
</payment>
<payment>
<id>8</id>
<date>2012-09-05T00:00:00-04:00</date>
<amount>1.0</amount>
<cardType>Amex</cardType>
</payment>
<payment>
<id>9</id>
<date>2012-09-05T00:00:00-04:00</date>
<amount>1.0</amount>
<cardType>Amex</cardType>
</payment>
<payment>
<id>10</id>
<date>2012-09-04T00:00:00-04:00</date>
<amount>89.0</amount>
<cardType>Amex</cardType>
</payment>
<payment>
<id>11</id>
<date>2012-09-04T00:00:00-04:00</date>
<amount>89.0</amount>
<cardType>Amex</cardType>
</payment>
<payment>
<id>12</id>
<date>2012-09-04T00:00:00-04:00</date>
<amount>12.0</amount>
<cardType>Amex</cardType>
</payment>
<payment>
<id>28</id>
<date>2012-09-13T00:00:00-04:00</date>
<amount>84375.34</amount>
<cardType>Amex</cardType>
</payment>
<payment>
<id>29</id>
<date>2012-09-13T00:00:00-04:00</date>
<amount>34.34</amount>
<cardType>Amex</cardType>
</payment>
<payment>
<id>33</id>
<date>2012-09-04T00:00:00-04:00</date>
<amount>23.42</amount>
<cardType>Amex</cardType>
</payment>
<payment>
<id>34</id>
<date>2012-09-04T00:00:00-04:00</date>
<amount>23.42</amount>
<cardType>Amex</cardType>
</payment>
<payment>
<id>35</id>
<date>2012-09-06T00:00:00-04:00</date>
<amount>34.0</amount>
<cardType>Amex</cardType>
</payment>
<payment>
<id>36</id>
<date>2012-09-06T00:00:00-04:00</date>
<amount>34.0</amount>
<cardType>Amex</cardType>
</payment>
<payment>
<id>37</id>
<date>2012-09-06T00:00:00-04:00</date>
<amount>34.0</amount>
<cardType>Amex</cardType>
</payment>
<payment>
<id>38</id>
<date>2012-09-06T00:00:00-04:00</date>
<amount>34.0</amount>
<cardType>Amex</cardType>
</payment>
<payment>
<id>39</id>
<date>2012-09-06T00:00:00-04:00</date>
<amount>2.0</amount>
<cardType>Amex</cardType>
</payment>
<payment>
<id>40</id>
<date>2012-09-06T00:00:00-04:00</date>
<amount>2.0</amount>
<cardType>Amex</cardType>
</payment>
</payments>
</CardPayments>

[Bear Bibeault]

But probably neglected to set the content-type correctly?

[sam jacksonville]

Thanks Bear. I have set the content type to response.setContentType("application/xml") in the servlet didn't work.

Even response.setContentType("text/xml") didn't help.


I am doing this in the javascript.

function handleGetCardName() {
	//Check to see if the XmlHttpRequests state is finished.
	alert("ready state: " + receiveReq.readyState + "status :" + receiveReq.status );
	if (receiveReq.readyState == 4 && receiveReq.status == 200) {
	//get the xml and display the table with payments for that card so far..
		{
			alert("ready state: " + receiveReq.readyState + "status :" + receiveReq.status );
		var xmlDoc = receiveReq.responseXML;
		alert("XML received via responseXML:" + xmlDoc);
		var paymentElements = xmlDoc.firstChild.nodeName;
		var payments = xmlDoc.getElementsByTagName('payment');
		for(var x=0;x<payments.length;x++)
		{
			var id = payments[x].getElementsByTagName('id').nodeValue;
			var date = payments[x].getElementsByTagName('date').nodeValue;
			//var amount = payments[x].getElementsByTagName('amount').childNodes[0].nodeValue;
		}
		alert("id: " + id + " " + "date : " + date + " ");// + "amount :" + amount);
		document.getElementById('writeroot').innerHTML = card + " " + paymentElements; 
		
		}

	}
}

[Bear Bibeault]

Have you used the browser's debugger to inspect the response to make sure it's formed exactly as you intend?

[Eric Pascarello]

Open the url into the browser that the Ajax request is going to, that will normally show you the error in your XML.

Eric

[Bear Bibeault]

XML generated by JAXB would assume to be correctly formed, but yeah, validating the XML is the next logical step if all of the response headers are correct.

[sam jacksonville]

Bear,
Thanks you. I checked inside the browser now and I am seeing the XML in the xmlDoc, wooo hooo!. I have attached a screenshot of it. So looks like the XML is coming back in the response.

But now I am loading this in to the browser's DOM parser using the DOM Parser code:

function handleGetCardName() {
	//Check to see if the XmlHttpRequests state is finished.
	alert("ready state: " + receiveReq.readyState + "status :" + receiveReq.status );
	if (receiveReq.readyState == 4 && receiveReq.status == 200) {
	//get the xml and display the table with payments for that card so far..
		{
			alert("ready state: " + receiveReq.readyState + "status :" + receiveReq.status );
		var xmlDoc = receiveReq.responseXML;
		alert("XML received via responseXML:" + xmlDoc);
		
		if (window.DOMParser)
		{
		parser=new DOMParser();
		xmlDoc=parser.parseFromString(xmlDoc,"text/xml");   //I am seeing the parser error mentioned below on this line. My XML is same as the one that I loaded in my original question.
		}
		else // Internet Explorer
		{
		xmlDoc=new ActiveXObject("Microsoft.XMLDOM");
		xmlDoc.async=false;
		xmlDoc.loadXML(xmlDoc); 
		}
		
		
		}

	}
}

I am getting the below parser error when I check in firebug.

<parsererror>
XML Parsing Error: syntax error Location: http://localhost:8080/MakePayments/index.jsp Line Number 1, Column 1:
<sourcetext>[object XMLDocument] ^</sourcetext>
</parsererror>

[g tsuji]

You do not do ever something like this

xmlDoc=parser.parseFromString(xmlDoc,"text/xml");

or this

xmlDoc.loadXML(xmlDoc);

even we are pardonning the self-fabricated confusion of xmlDoc, one referring to .responseXML the other from being a reference to a parser instance created anew. The xmlDoc referring to .responseXML is an object not a String loosely speaking. So the last post is a regression rather than progression toward resolving a problem, whatever it is.

If you want to re-build the document and that you have .responseText error free, you can do that with .responseText (not with .responseXML).

If you stick the approach using responseXML, your successive posts are ambiguous. At some places, it seems you get responseXML non null, at others, null. In any case, if responseXML is corrected populated with the proper setting up server-side on the contentType, the only thing you should have to change is this.

        //var paymentElements = xmlDoc.firstChild.nodeName;    //line #10
        var paymentElements = xmlDoc.documentElement.nodeName;    //the correct way

The reason is that xmlDoc being the document object, its "firstChild" might not be the root element. So the result of that line is far from stable, and it might result in something else rather than the root element.

[Bear Bibeault]

In other words, the XML has already been parsed and you are trying to re-parse a DOM.

[sam jacksonville]

Thanks Guys...It all worked out fine...I learnt a lot from this. Appreciate your help Bear, g tsuji and Eric.

[Bear Bibeault]