Transforming XML to HTML can be accomplished through the use of XSLT templates

To convert XML to another XML format using XSLT (Extensible Stylesheet Language Transformations). It reads an XML file and applies an XSLT stylesheet to transform the XML data into a different format, such as HTML.

Let's break down the code to understand its functionality and purpose, and I'll also point out a few potential improvements.

Breakdown of the Key Components:

Main Functionality:

The main method loads the input XML from a file (breakFirst.xml) and an XSLT stylesheet (breakFirst.xslt), then applies the transformation and outputs the result.

Converting XML File to String:

The method convertXMLFileToString(String fileName) converts the XML file into a string for easier processing. It uses the DocumentBuilderFactory to read the XML file into a DOM object, then transforms it into a string format.

XSLT Transformation:

The transform(String xmlDataInput, Templates xsltTemplate) method applies the XSLT stylesheet to the provided XML data and returns the transformed result. The Templates object is created using the XSLT file.

Creating the XSLT Template:

createTemplate() reads the XSLT file into a Templates object, which is then used for the transformation.

Example Flow:

You have an XML file, breakFirst.xml, containing breakfast menu items, and an XSLT stylesheet, breakFirst.xslt, which defines how to transform that XML into an HTML page.
The XmlToXmlConvert class will read both the XML and XSLT, perform the transformation, and output the transformed content.

Output:

In this case, the transformation will produce an HTML page displaying the breakfast menu items styled with a teal background and white text, as defined in the XSLT.

xslt

<?xml version="1.0" encoding="UTF-8"?>

<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0">

<xsl:output indent="yes" method="html"/>

<xsl:template match="/">

<html>

<xsl:for-each select="breakfast_menu/food">

<xsl:value-of select="price"/>

</div>

<p>

<xsl:value-of select="description"/>

<span style="font-style:italic"> (<xsl:value-of select="calories"/> calories per serving)</span>

</p>

</div>

</xsl:for-each>

</body>

</html>

</xsl:template>

</xsl:stylesheet>

xml

<?xml version="1.0" encoding="UTF-8"?>

<breakfast_menu>

<food>

<name>Belgian Waffles</name>

<description>Two of our famous Belgian Waffles with plenty of real maple syrup</description>

</food>

<food>

<name>Strawberry Belgian Waffles</name>

<description>Light Belgian waffles covered with strawberries and whipped cream</description>

</food>

<food>

<name>Berry-Berry Belgian Waffles</name>

<description>Light Belgian waffles covered with an assortment of fresh berries and whipped cream</description>

</food>

<food>

<name>French Toast</name>

<description>Thick slices made from our homemade sourdough bread</description>

</food>

<food>

<name>Homestyle Breakfast</name>

<description>Two eggs, bacon or sausage, toast, and our ever-popular hash browns</description>

</food>

</breakfast_menu>

java

package com.kartik.xml.to.xml;

import java.io.*;

import javax.xml.parsers.DocumentBuilderFactory;

import javax.xml.transform.*;

import javax.xml.transform.dom.DOMSource;

import javax.xml.transform.stream.StreamResult;

import javax.xml.transform.stream.StreamSource;

public class XmlToXmlConvert {

public static void main(String[] args) {

try {

// Convert XML file to string

String dataXML = convertXMLFileToString("C:\\Users\\kmandal\\Desktop\\breakFirst.xml");

// Create XSLT template

Templates xsltTemplate = createTemplate("C:\\Users\\kmandal\\Desktop\\breakFirst.xslt");

// Perform the transformation

XmlToXmlConvert converter = new XmlToXmlConvert();

String output = converter.transform(dataXML, xsltTemplate);

// Output the transformed content

System.out.println(output);

} catch (Exception e) {

e.printStackTrace();

}

/**

* Transform XML using XSLT template

* @param xmlDataInput - XML data as string

* @param xsltTemplate - XSLT template for transformation

* @return Transformed XML or HTML as string

public String transform(String xmlDataInput, Templates xsltTemplate) {

if (xmlDataInput == null || xmlDataInput.trim().isEmpty() || xsltTemplate == null) {

return null;

}

try (StringWriter stringWriter = new StringWriter()) {

Transformer transformer = xsltTemplate.newTransformer();

StreamSource source = new StreamSource(new StringReader(xmlDataInput));

StreamResult result = new StreamResult(stringWriter);

transformer.transform(source, result);

return stringWriter.toString();

} catch (Exception e) {

throw new RuntimeException("Error in XSLT transformation", e);

}

/**

* Create an XSLT template from a file

* @param xsltFilePath - Path to XSLT file

* @return XSLT Template object

* @throws Exception in case of error

public static Templates createTemplate(String xsltFilePath) throws Exception {

TransformerFactory tFactory = TransformerFactory.newInstance();

try (FileReader reader = new FileReader(xsltFilePath)) {

StreamSource stylesource = new StreamSource(reader);

return tFactory.newTemplates(stylesource);

} catch (Exception e) {

throw new RuntimeException("Error in creating XSLT template", e);

}

/**

* Convert an XML file to a string

* @param fileName - Path to XML file

* @return XML as string

* @throws Exception in case of error

public static String convertXMLFileToString(String fileName) throws Exception {

DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory.newInstance();

try (InputStream inputStream = new FileInputStream(new File(fileName))) {

org.w3c.dom.Document doc = documentBuilderFactory.newDocumentBuilder().parse(inputStream);

StringWriter stw = new StringWriter();

Transformer serializer = TransformerFactory.newInstance().newTransformer();

serializer.transform(new DOMSource(doc), new StreamResult(stw));

return stw.toString();

}

Output

<html>

<span style="font-weight:bold">Belgian Waffles - </span>$5.95</div>

<p>Two of our famous Belgian Waffles with plenty of real maple syrup<span style="font-style:italic"> (650 calories per serving)</span>

</p>

</div>

<span style="font-weight:bold">Strawberry Belgian Waffles - </span>$7.95</div>

<p>Light Belgian waffles covered with strawberries and whipped cream<span style="font-style:italic"> (900 calories per serving)</span>

</p>

</div>

<span style="font-weight:bold">Berry-Berry Belgian Waffles - </span>$8.95</div>

<p>Light Belgian waffles covered with an assortment of fresh berries and whipped cream<span style="font-style:italic"> (900 calories per serving)</span>

</p>

</div>

<span style="font-weight:bold">French Toast - </span>$4.50</div>

<p>Thick slices made from our homemade sourdough bread<span style="font-style:italic"> (600 calories per serving)</span>

</p>

</div>

<span style="font-weight:bold">Homestyle Breakfast - </span>$6.95</div>

<p>Two eggs, bacon or sausage, toast, and our ever-popular hash browns<span style="font-style:italic"> (950 calories per serving)</span>

</p>

</div>

</body>

</html>

Key Changes:

Exception Handling: Improved error handling with try-catch blocks.
File Handling: Used try-with-resources to automatically close file streams.
Flexibility: File paths for XML and XSLT are passed as parameters.

This version reads the XML and XSLT files, applies the transformation, and prints the transformed result. You can save the result to an HTML file if required.