1. Overview
The Spring web framework is built around the MVC (Model-View-Controller) pattern, which makes it easier to separate concerns in an application. This allows for the possibility to use different view technologies, from the well established JSP technology to a variety of template engines.
In this article, we’re going to take a look at the main template engines that can be used with Spring, their configuration, and examples of use.
2. Spring View Technologies
Given that concerns in a Spring MVC application are cleanly separated switching from one view technology to another is primarily a matter of configuration.
To render each view type, we need to define a ViewResolver bean corresponding to each technology. This means that we can then return the view names from @Controller mapping methods in the same way we usually return JSP files.
In the following sections, we’re going to go over more traditional technologies like Java Server Pages, as well as the main template engines that can be used with Spring: Thymeleaf, Groovy, FreeMarker, Jade.
For each of these, we will go over the configuration necessary both in a standard Spring application and an application built using Spring Boot.
3. Java Server Pages
JSP is one of the most popular view technologies for Java applications, and it is supported by Spring out-of-the-box. For rendering JSP files, a commonly used type of ViewResolver bean is InternalResourceViewResolver:
@EnableWebMvc
@Configuration
public class ApplicationConfiguration extends WebMvcConfigurerAdapter {
@Bean
public ViewResolver jspViewResolver() {
InternalResourceViewResolver bean = new InternalResourceViewResolver();
bean.setPrefix("/WEB-INF/views/");
bean.setSuffix(".jsp");
return bean;
}
}
Next, we can start creating JSP files in the /WEB-INF/views location:
<%@ taglib prefix="form" uri="http://www.springframework.org/tags/form"%>
<html>
<head>
<meta http-equiv="Content-Type"
content="text/html; charset=ISO-8859-1">
<title>User Registration</title>
</head>
<body>
<form:form method="POST" modelAttribute="user">
<form:label path="email">Email: </form:label>
<form:input path="email" type="text"/>
<form:label path="password">Password: </form:label>
<form:input path="password" type="password" />
<input type="submit" value="Submit" />
</form:form>
</body>
</html>
If we are adding the files to a Spring Boot application, then instead of in the ApplicationConfiguration class, we can define the following properties in an application.properties file:
spring.mvc.view.prefix: /WEB-INF/views/ spring.mvc.view.suffix: .jsp
Based on these properties, Spring Boot will auto-configure the necessary ViewResolver.
4. Thymeleaf
Thymeleaf is a Java template engine which can process HTML, XML, text, JavaScript or CSS files. Unlike other template engines, Thymeleaf allows using templates as prototypes, meaning they can be viewed as static files.
4.1. Maven Dependencies
To integrate Thymeleaf with Spring, we need to add the thymeleaf and thymeleaf-spring4 dependencies:
<dependency>
<groupId>org.thymeleaf</groupId>
<artifactId>thymeleaf</artifactId>
<version>3.0.7.RELEASE</version>
</dependency>
<dependency>
<groupId>org.thymeleaf</groupId>
<artifactId>thymeleaf-spring4</artifactId>
<version>3.0.7.RELEASE</version>
</dependency>
If we have a Spring 3 project, then we need to add thymeleaf-spring3.
4.2. Spring Configuration
Next, we need to add the configuration which requires a SpringTemplateEngine bean, as well as a TemplateResolver bean that specifies the location and type of the view files.
The SpringResourceTemplateResolver is integrated with Spring’s resource resolution mechanism:
@Configuration
@EnableWebMvc
public class ThymeleafConfiguration {
@Bean
public SpringTemplateEngine templateEngine() {
SpringTemplateEngine templateEngine = new SpringTemplateEngine();
templateEngine.setTemplateResolver(thymeleafTemplateResolver());
return templateEngine;
}
@Bean
public SpringResourceTemplateResolver thymeleafTemplateResolver() {
SpringResourceTemplateResolver templateResolver
= new SpringResourceTemplateResolver();
templateResolver.setPrefix("/WEB-INF/views/");
templateResolver.setSuffix(".html");
templateResolver.setTemplateMode("HTML5");
return templateResolver;
}
}
Also, we need a ViewResolver bean of type ThymeleafViewResolver:
@Bean
public ThymeleafViewResolver thymeleafViewResolver() {
ThymeleafViewResolver viewResolver = new ThymeleafViewResolver();
viewResolver.setTemplateEngine(templateEngine());
return viewResolver;
}
4.3. Thymeleaf Templates
Now we can add an HTML file in the WEB-INF/views location:
<html>
<head>
<meta charset="ISO-8859-1" />
<title>User Registration</title>
</head>
<body>
<form action="#" th:action="@{/register}"
th:object="${user}" method="post">
Email:<input type="text" th:field="*{email}" />
Password:<input type="password" th:field="*{password}" />
<input type="submit" value="Submit" />
</form>
</body>
</html>
Thymeleaf templates are very similar in syntax to HTML templates.
Some of the features that are available when using Thymeleaf in a Spring application are:
- support for defining forms behavior
- binding form inputs to data models
- validation for form inputs
- displaying values from message sources
- rendering template fragments
You can read more about using Thymeleaf templates in our article Thymeleaf in Spring MVC.
4.4. Thymeleaf in Spring Boot
Spring Boot will provide auto-configuration for Thymeleaf by adding the spring-boot-starter-thymeleaf dependency:
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-thymeleaf</artifactId>
<version>1.5.6.RELEASE</version>
</dependency>
No explicit configuration is necessary. By default, HTML files should be placed in the resources/templates location.
5. FreeMarker
FreeMarker is a Java-based template engine built by the Apache Software Foundation. It can be used to generate web pages, but also source code, XML files, configuration files, emails and other text-based formats.
The generation is done based on template files written using the FreeMarker Template Language.
5.1. Maven Dependencies
To start using the templates in our project, we need the freemarker dependency:
<dependency>
<groupId>org.freemarker</groupId>
<artifactId>freemarker</artifactId>
<version>2.3.23</version>
</dependency>
For Spring integration, we also need the spring-context-support dependency:
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context-support</artifactId>
<version>4.3.10.RELEASE</version>
</dependency>
5.2. Spring Configuration
Integrating FreeMarker with Spring MVC requires defining a FreemarkerConfigurer bean which specifies the location of the template files:
@Configuration
@EnableWebMvc
public class FreemarkerConfiguration {
@Bean
public FreeMarkerConfigurer freemarkerConfig() {
FreeMarkerConfigurer freeMarkerConfigurer = new FreeMarkerConfigurer();
freeMarkerConfigurer.setTemplateLoaderPath("/WEB-INF/views/");
return freeMarkerConfigurer;
}
}
Next, we need to define an appropriate ViewResolver bean of type FreeMarkerViewResolver:
@Bean
public FreeMarkerViewResolver freemarkerViewResolver() {
FreeMarkerViewResolver resolver = new FreeMarkerViewResolver();
resolver.setCache(true);
resolver.setPrefix("");
resolver.setSuffix(".ftl");
return resolver;
}
5.3. FreeMarker Templates
We can create an HTML template using FreeMarker in the WEB-INF/views location:
<#import "/spring.ftl" as spring/>
<html>
<head>
<meta charset="ISO-8859-1" />
<title>User Registration</title>
</head>
<body>
<form action="register" method="post">
<@spring.bind path="user" />
Email: <@spring.formInput "user.email"/>
Password: <@spring.formPasswordInput "user.password"/>
<input type="submit" value="Submit" />
</form>
</body>
</html>
In the example above, we have imported a set of macros defined by Spring for working with forms in FreeMarker, including binding form inputs to data models.
Also, the FreeMarker Template Language contains a large number of tags, directives, and expressions for working with collections, flow control structures, logical operators, formatting and parsing strings, numbers and many more features.
5.4. FreeMarker in Spring Boot
In a Spring Boot application, we can simplify the needed configuration by using the spring-boot-starter-freemarker dependency:
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-freemarker</artifactId>
<version>1.5.6.RELEASE</version>
</dependency>
This starter adds the necessary auto-configuration. All we need to do is start placing our template files in the resources/templates folder.
6. Groovy
Spring MVC views can also be generated using the Groovy Markup Template Engine. This engine is based on a builder syntax and can be used for generating any text format.
6.1. Maven Dependencies
The groovy-templates dependency needs to be added to our pom.xml:
<dependency>
<groupId>org.codehaus.groovy</groupId>
<artifactId>groovy-templates</artifactId>
<version>2.4.12</version>
</dependency>
6.2. Spring Configuration
The integration of the Markup Template Engine with Spring MVC requires defining a GroovyMarkupConfigurer bean and a ViewResolver of type GroovyMarkupViewResolver:
@Configuration
@EnableWebMvc
public class GroovyConfiguration {
@Bean
public GroovyMarkupConfigurer groovyMarkupConfigurer() {
GroovyMarkupConfigurer configurer = new GroovyMarkupConfigurer();
configurer.setResourceLoaderPath("/WEB-INF/views/");
return configurer;
}
@Bean
public GroovyMarkupViewResolver thymeleafViewResolver() {
GroovyMarkupViewResolver viewResolver = new GroovyMarkupViewResolver();
viewResolver.setSuffix(".tpl");
return viewResolver;
}
}
6.3. Groovy Markup Templates
Templates are written in the Groovy language and have several characteristics:
- they are compiled into bytecode
- they contain support for fragments and layouts
- they provide support for internationalization
- the rendering is fast
Let’s create a Groovy template for our “User Registration” form, which includes data bindings:
yieldUnescaped '<!DOCTYPE html>'
html(lang:'en') {
head {
meta('http-equiv':'"Content-Type" ' +
'content="text/html; charset=utf-8"')
title('User Registration')
}
body {
form (id:'userForm', action:'register', method:'post') {
label (for:'email', 'Email')
input (name:'email', type:'text', value:user.email?:'')
label (for:'password', 'Password')
input (name:'password', type:'password', value:user.password?:'')
div (class:'form-actions') {
input (type:'submit', value:'Submit')
}
}
}
}
6.4. Groovy Template Engine in Spring Boot
Spring Boot contains auto-configuration for the Groovy Template Engine, which is added by including the spring-boot-starter-groovy-templates dependency:
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-groovy-templates</artifactId>
<version>1.5.6.RELEASE</version>
</dependency>
The default location for the templates is /resources/templates.
7. Jade4j
Jade4j is the Java implementation of the Pug template engine (originally known as Jade) for Javascript. Jade4j templates can be used for generating HTML files.
7.1. Maven Dependencies
For Spring integration, we need the spring-jade4j dependency:
<dependency> <groupId>de.neuland-bfi</groupId> <artifactId>spring-jade4j</artifactId> <version>1.2.5</version> </dependency>
7.2. Spring Configuration
To use Jade4j with Spring, we have to define a SpringTemplateLoader bean that configures the location of the templates, as well as a JadeConfiguration bean:
@Configuration
@EnableWebMvc
public class JadeTemplateConfiguration {
@Bean
public SpringTemplateLoader templateLoader() {
SpringTemplateLoader templateLoader
= new SpringTemplateLoader();
templateLoader.setBasePath("/WEB-INF/views/");
templateLoader.setSuffix(".jade");
return templateLoader;
}
@Bean
public JadeConfiguration jadeConfiguration() {
JadeConfiguration configuration
= new JadeConfiguration();
configuration.setCaching(false);
configuration.setTemplateLoader(templateLoader());
return configuration;
}
}
Next, we need the usual ViewResolver bean, in this case of type JadeViewResolver:
@Bean
public ViewResolver viewResolver() {
JadeViewResolver viewResolver = new JadeViewResolver();
viewResolver.setConfiguration(jadeConfiguration());
return viewResolver;
}
7.3. Jade4j Templates
Jade4j templates are characterized by an easy-to-use whitespace-sensitive syntax:
doctype html
html
head
title User Registration
body
form(action="register" method="post" )
label(for="email") Email:
input(type="text" name="email")
label(for="password") Password:
input(type="password" name="password")
input(type="submit" value="Submit")
The project also provides a very useful interactive documentation, where you can view the output of your template as you write it.
Spring Boot does not provide a Jade4j starter, so in a Boot project, we would have to add the same Spring configuration as defined above.
8. Other Template Engines
Besides the template engines described so far, there are quite a few more available which may be used.
Let’s review some of the briefly.
Velocity is an older template engine, which is very complex but has the disadvantage that Spring has deprecated its use since version 4.3.
JMustache is a template engine which can be easily integrated into a Spring Boot application by using the spring-boot-starter-mustache dependency.
Pebble contains support for Spring and Spring Boot within its libraries.
Other templating libraries such as Handlebars or React, running on top of a JSR-223 script engine such as Nashorn, can also be used.
9. Conclusion
In this article, we have gone over some of the most popular template engines for Spring web applications.
And, as always, the full source code of the examples can be found over on GitHub.