XML write set attribute with xml namespace

I am trying to write an xml file, where i need to write the xml namespace and its URI as below.

<node xmlns:xml="http://www.w3.org/XML/1998/namespace" >
......
.....
</node>

I understand that this is completely optional and its okay if we don't write it. But i need it as that is expected to be done.

I am using xmlwrite function as using older matlab version, so don't have writeStruct function. When i am writing below code somehow matlab is not writing the xml namespace in the xml file. I think it is because it is preserved but i am not able to get any workaround it.

Can you please help on this ?

docNode = com.mathworks.xml.XMLUtils.createDocument('node');

rootElement = docNode.getDocumentElement;
rootElement.setAttribute('xmlns:xml','http://www.w3.org/XML/1998/namespace');
rootElement.setAttribute('xmlns:2xml','http://www.w3.org/XML/1998/namespace');

xmlwrite('test.xml',docNode);

[Mihai]

Try:

docNode = com.mathworks.xml.XMLUtils.createDocument('node');

rootElement = docNode.getDocumentElement;

rootElement.setAttributeNS('http://www.w3.org/2000/xmlns/', 'xmlns:xml', 'http://www.w3.org/XML/1998/namespace');

[vivek patel]

Hi,

I tried but unfortunately it is not working, i have tried in MATLAB 2016b and MATLAB 2021a versions. Is it working in some other versions ?

Answer 1

[Meet]

Hi Vivek,

The “xml” prefix is reserved, which may cause MATLAB to omit it during the writing process.

As a workaround, you might consider manually editing the XML file after it is generated to include the namespace, you can look it into the code below:

% Import all classes and functions from the matlab.io.xml.dom package
import matlab.io.xml.dom.*

% Create a new XML document with a root element named "node"
docNode = Document("node");

% Retrieve the root element of the XML document
docRootNode = getDocumentElement(docNode);

% Set an attribute with a namespace for the root element
% "http://www.w3.org/2000/xmlns/" is the standard URI for XML namespaces
% "xmlns:xml" is the attribute name, and "http://www.w3.org/XML/1998/namespace" is its value
docRootNode.setAttributeNS("http://www.w3.org/2000/xmlns/", "xmlns:xml", "http://www.w3.org/XML/1998/namespace");

% Name of the XML file
xmlFileName = "test.xml";

% Create a DOMWriter object to handle writing the XML document to a file
writer = matlab.io.xml.dom.DOMWriter;

% Write the XML document to the specified file using the writer object
writeToFile(writer, docNode, xmlFileName);

Note: matlab.io.xml.dom.DOMWriter was introduced in MATLAB R2021a.

You can refer to the resources below for more information:

1. DOMWriter: https://www.mathworks.com/help/matlab/ref/matlab.io.xml.dom.domwriter-class.html
2. setAttributeNS: https://developer.mozilla.org/en-US/docs/Web/API/Element/setAttributeNS