XSLT Views

XSLT is a transformation language for XML and is popular as a view technology within web applications. XSLT can be a good choice as a view technology if your application naturally deals with XML or if your model can easily be converted to XML. The following section shows how to produce an XML document as model data and have it transformed with XSLT in a Spring Web MVC application.

This example is a trivial Spring application that creates a list of words in the Controller and adds them to the model map. The map is returned, along with the view name of our XSLT view. See Annotated Controllers for details of Spring Web MVC’s Controller interface. The XSLT controller turns the list of words into a simple XML document ready for transformation.

Beans

Configuration is standard for a simple Spring web application: The MVC configuration has to define an XsltViewResolver bean and regular MVC annotation configuration. The following example shows how to do so:

Java
Kotlin

@EnableWebMvc
@ComponentScan
@Configuration
public class WebConfig implements WebMvcConfigurer {

	@Bean
	public XsltViewResolver xsltViewResolver() {
		XsltViewResolver viewResolver = new XsltViewResolver();
		viewResolver.setPrefix("/WEB-INF/xsl/");
		viewResolver.setSuffix(".xslt");
		return viewResolver;
	}
}

@EnableWebMvc
@ComponentScan
@Configuration
class WebConfig : WebMvcConfigurer {

	@Bean
	fun xsltViewResolver() = XsltViewResolver().apply {
		setPrefix("/WEB-INF/xsl/")
		setSuffix(".xslt")
	}
}

Controller

We also need a Controller that encapsulates our word-generation logic.

The controller logic is encapsulated in a @Controller class, with the handler method being defined as follows:

Java
Kotlin

@Controller
public class XsltController {

	@RequestMapping("/")
	public String home(Model model) throws Exception {
		Document document = DocumentBuilderFactory.newInstance().newDocumentBuilder().newDocument();
		Element root = document.createElement("wordList");

		List<String> words = Arrays.asList("Hello", "Spring", "Framework");
		for (String word : words) {
			Element wordNode = document.createElement("word");
			Text textNode = document.createTextNode(word);
			wordNode.appendChild(textNode);
			root.appendChild(wordNode);
		}

		model.addAttribute("wordList", root);
		return "home";
	}
}

import org.springframework.ui.set

@Controller
class XsltController {

	@RequestMapping("/")
	fun home(model: Model): String {
		val document = DocumentBuilderFactory.newInstance().newDocumentBuilder().newDocument()
		val root = document.createElement("wordList")

		val words = listOf("Hello", "Spring", "Framework")
		for (word in words) {
			val wordNode = document.createElement("word")
			val textNode = document.createTextNode(word)
			wordNode.appendChild(textNode)
			root.appendChild(wordNode)
		}

		model["wordList"] = root
		return "home"
	}
}

So far, we have only created a DOM document and added it to the Model map. Note that you can also load an XML file as a Resource and use it instead of a custom DOM document.

There are software packages available that automatically 'domify' an object graph, but, within Spring, you have complete flexibility to create the DOM from your model in any way you choose. This prevents the transformation of XML playing too great a part in the structure of your model data, which is a danger when using tools to manage the DOMification process.

Transformation

Finally, the XsltViewResolver resolves the “home” XSLT template file and merges the DOM document into it to generate our view. As shown in the XsltViewResolver configuration, XSLT templates live in the war file in the WEB-INF/xsl directory and end with an xslt file extension.

The following example shows an XSLT transform:

<?xml version="1.0" encoding="utf-8"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">

	<xsl:output method="html" omit-xml-declaration="yes"/>

	<xsl:template match="/">
		<html>
			<head><title>Hello!</title></head>
			<body>
				<h1>My First Words</h1>
				<ul>
					<xsl:apply-templates/>
				</ul>
			</body>
		</html>
	</xsl:template>

	<xsl:template match="word">
		<li><xsl:value-of select="."/></li>
	</xsl:template>

</xsl:stylesheet>

The preceding transform is rendered as the following HTML:

<html>
	<head>
		<META http-equiv="Content-Type" content="text/html; charset=UTF-8">
		<title>Hello!</title>
	</head>
	<body>
		<h1>My First Words</h1>
		<ul>
			<li>Hello</li>
			<li>Spring</li>
			<li>Framework</li>
		</ul>
	</body>
</html>