Spring Boot adding thymeleaf-layout-dialect - spring-mvc

Question

I am using spring boot (v1.5.3.BUILD-SNAPSHOT)
I am new to spring boot.
Using gradle
Note that the normal thymeleaf dialect works fine (th:...)
spring-boot-starter-thymeleaf\1.5.3.BUILD-SNAPSHOT
I want to add thymeleaf-layout-dialect
I added the dependency
compile('nz.net.ultraq.thymeleaf:thymeleaf-layout-dialect')
the documentation says to add the dialect by doing the following
TemplateEngine templateEngine = new TemplateEngine(); // Or
SpringTemplateEngine for Spring config
templateEngine.addDialect(new LayoutDialect());
So i added a configuration class
#Configuration
public class MyConfiguration {
#Bean
public SpringTemplateEngine templateEngine(){
SpringTemplateEngine templateEngine = new SpringTemplateEngine();
templateEngine.addDialect(new LayoutDialect());
return templateEngine;
}
}
but when I try running the app I get the following error
org.thymeleaf.exceptions.ConfigurationException: Cannot initialize: no template resolvers have been set
at org.thymeleaf.Configuration.initialize(Configuration.java:203) ~[thymeleaf-2.1.5.RELEASE.jar:2.1.5.RELEASE]
at org.thymeleaf.TemplateEngine.initialize(TemplateEngine.java:827) ~[thymeleaf-2.1.5.RELEASE.jar:2.1.5.RELEASE]
at org.thymeleaf.spring4.view.ThymeleafView.renderFragment(ThymeleafView.java:203) ~[thymeleaf-spring4-2.1.5.RELEASE.jar:2.1.5.RELEASE]
at org.thymeleaf.spring4.view.ThymeleafView.render(ThymeleafView.java:190) ~[thymeleaf-spring4-2.1.5.RELEASE.jar:2.1.5.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1282) ~[spring-webmvc-4.3.8.BUILD-SNAPSHOT.jar:4.3.8.BUILD-SNAPSHOT]
at org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:1037) ~[spring-webmvc-4.3.8.BUILD-SNAPSHOT.jar:4.3.8.BUILD-SNAPSHOT]
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:980) ~[spring-webmvc-4.3.8.BUILD-SNAPSHOT.jar:4.3.8.BUILD-SNAPSHOT]
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:897) ~[spring-webmvc-4.3.8.BUILD-SNAPSHOT.jar:4.3.8.BUILD-SNAPSHOT]
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970) ~[spring-webmvc-4.3.8.BUILD-SNAPSHOT.jar:4.3.8.BUILD-SNAPSHOT]
Can someone tell me how to add the thymeleaf-layout-dialect correctly?

Answer 1

The issue is:
org.thymeleaf.exceptions.ConfigurationException: Cannot initialize: no template resolvers have been set
To integrate Thymeleaf with Spring, you need to configure 3 beans:
ThymeleafViewResolver Bean - You would be set it with a template engine
SpringTemplateEngine Bean - You would be set it with a template resolver
TemplateResolver Bean
In your templateEngine bean you didn't set any template resolver, so you might change your templateEngine() method as following:
#Bean
public SpringTemplateEngine templateEngine(TemplateResolver templateResolver){
SpringTemplateEngine templateEngine = new SpringTemplateEngine();
templateEngine.setTemplateResolver(templateResolver);
templateEngine.addDialect(new LayoutDialect());
return templateEngine;
}
Spring will provide you with a templateResolver bean of SpringTemplateEngine.
BTW If you define spring-boot-starter-thymeleaf as dependency, it will provide thymeleaf-layout-dialect as a dependency with the convenient version, then Spring will use ThymeleafAutoConfiguration.java - Spring Boot 1.5.x to configure a default beans for the three required beans.
For example:
LayoutDialect bean is define here ThymeleafWebLayoutConfiguration.ThymeleafWebLayoutConfiguration():
#Configuration
#ConditionalOnClass(name = "nz.net.ultraq.thymeleaf.LayoutDialect")
protected static class ThymeleafWebLayoutConfiguration {
#Bean
#ConditionalOnMissingBean
public LayoutDialect layoutDialect() {
return new LayoutDialect();
}
}
SpringTemplateEngine bean is defined with a template resolver and dialect from here ThymeleafWebLayoutConfiguration.ThymeleafDefaultConfiguration():
#Configuration
#ConditionalOnMissingBean(SpringTemplateEngine.class)
protected static class ThymeleafDefaultConfiguration {
private final Collection<ITemplateResolver> templateResolvers;
private final Collection<IDialect> dialects;
public ThymeleafDefaultConfiguration(
Collection<ITemplateResolver> templateResolvers,
ObjectProvider<Collection<IDialect>> dialectsProvider) {
this.templateResolvers = templateResolvers;
this.dialects = dialectsProvider.getIfAvailable();
}
#Bean
public SpringTemplateEngine templateEngine() {
SpringTemplateEngine engine = new SpringTemplateEngine();
for (ITemplateResolver templateResolver : this.templateResolvers) {
engine.addTemplateResolver(templateResolver);
}
if (!CollectionUtils.isEmpty(this.dialects)) {
for (IDialect dialect : this.dialects) {
engine.addDialect(dialect);
}
}
return engine;
}
}
And finally a thymeleafViewResolver bean is defined here AbstractThymeleafViewResolverConfiguration.thymeleafViewResolver():
#Bean
#ConditionalOnMissingBean(name = "thymeleafViewResolver")
#ConditionalOnProperty(name = "spring.thymeleaf.enabled", matchIfMissing = true)
public ThymeleafViewResolver thymeleafViewResolver() {
ThymeleafViewResolver resolver = new ThymeleafViewResolver();
configureTemplateEngine(resolver, this.templateEngine);
resolver.setCharacterEncoding(this.properties.getEncoding().name());
resolver.setContentType(appendCharset(this.properties.getContentType(),
resolver.getCharacterEncoding()));
resolver.setExcludedViewNames(this.properties.getExcludedViewNames());
resolver.setViewNames(this.properties.getViewNames());
// This resolver acts as a fallback resolver (e.g. like a
// InternalResourceViewResolver) so it needs to have low precedence
resolver.setOrder(Ordered.LOWEST_PRECEDENCE - 5);
resolver.setCache(this.properties.isCache());
return resolver;
}
which is extended by ThymeleafAutoConfiguration.Thymeleaf2ViewResolverConfiguration:
#Bean
#ConditionalOnMissingBean(name = "thymeleafViewResolver")
#ConditionalOnProperty(name = "spring.thymeleaf.enabled", matchIfMissing = true)
public ThymeleafViewResolver thymeleafViewResolver() {
ThymeleafViewResolver resolver = new ThymeleafViewResolver();
configureTemplateEngine(resolver, this.templateEngine);
resolver.setCharacterEncoding(this.properties.getEncoding().name());
resolver.setContentType(appendCharset(this.properties.getContentType(),
resolver.getCharacterEncoding()));
resolver.setExcludedViewNames(this.properties.getExcludedViewNames());
resolver.setViewNames(this.properties.getViewNames());
// This resolver acts as a fallback resolver (e.g. like a
// InternalResourceViewResolver) so it needs to have low precedence
resolver.setOrder(Ordered.LOWEST_PRECEDENCE - 5);
resolver.setCache(this.properties.isCache());
return resolver;
}
Hope it is clear now.