Develop Reference

How to use TWO SpringResourceTemplateResolver Beans?

Since Thymeleaf 3, Thymeleaf prefers the use of SpringResourceTemplateResolver (https://www.thymeleaf.org/doc/articles/thymeleaf3migration.html). So I decided to go from ClassLoaderTemplateResolver to SpringResourceTemplateResolver:
#Configuration
#EnableWebMvc
public class MvcConfig implements WebMvcConfigurer {
#Override
public void addResourceHandlers(ResourceHandlerRegistry registry) {
registry.addResourceHandler("/**").addResourceLocations("classpath:/static/");
registry.setOrder(1);
}
#Bean
public SpringResourceTemplateResolver templateResolver() {
SpringResourceTemplateResolver resolver = new SpringResourceTemplateResolver();
resolver.setPrefix("/templates/");
resolver.setSuffix(".html");
resolver.setTemplateMode(TemplateMode.HTML);
resolver.setCharacterEncoding("UTF-8");
resolver.setOrder(0);
resolver.setCheckExistence(true);
return resolver;
}
#Bean
public SpringResourceTemplateResolver templateResolver2() {
SpringResourceTemplateResolver resolver = new SpringResourceTemplateResolver();
resolver.setPrefix("/templates-2/");
resolver.setSuffix(".html");
resolver.setTemplateMode(TemplateMode.HTML);
resolver.setCharacterEncoding("UTF-8");
resolver.setOrder(1);
resolver.setCheckExistence(true);
return resolver;
}
}
Unfortunately, when implementig like this, I'll get an error:
Error resolving template [index], template might not exist or might not be accessible by any of the configured Template Resolvers.
To be honest, I've simple replaced ClassLoaderTemplateResolver with SpringResourceTemplateResolver in the hope, this will work. It doesn't. But searching for a working solution dealing with two template locations, all I find are outdated samples using ClassLoaderTemplateResolvers.
Trying to implement the code snippet provided by Thymeleaf as shown here https://www.thymeleaf.org/doc/articles/thymeleaf3migration.html won't work either when using two template directories, besides the fact, that this code itself uses the deprecated WebMvcConfigurerAdapter.
Is there any example how to configure a Spring Boot application using Thymeleaf having two or more template locations which isn't completely outdated?

So after a while and many many tryouts I've finally got the templates working. Since there isn't any decent answer to my question flying round the internet, I will post my solution for others:
#Configuration
public class ThymeleafConfig implements ApplicationContextAware {
private ApplicationContext applicationContext;
#Override
public void setApplicationContext(#Autowired ApplicationContext applicationContext) {
this.applicationContext = applicationContext;
}
#Bean
public SpringResourceTemplateResolver templateResolver() {
SpringResourceTemplateResolver templateResolver = new SpringResourceTemplateResolver();
templateResolver.setApplicationContext(this.applicationContext);
templateResolver.setPrefix("classpath:/templates-1/");
templateResolver.setSuffix(".html");
templateResolver.setTemplateMode(TemplateMode.HTML);
templateResolver.setCharacterEncoding("UTF-8");
templateResolver.setOrder(1);
templateResolver.setCheckExistence(true); /* FYI: necessary to chain TemplateResolvers */
templateResolver.setCacheable(false); /* FYI: during development -> false, so that we can see changes we make */
return templateResolver;
}
#Bean
public SpringResourceTemplateResolver templateResolver2() {
SpringResourceTemplateResolver templateResolver = new SpringResourceTemplateResolver();
templateResolver.setApplicationContext(this.applicationContext);
templateResolver.setPrefix("classpath:/templates-2/");
templateResolver.setSuffix(".html");
templateResolver.setTemplateMode(TemplateMode.HTML);
templateResolver.setCharacterEncoding("UTF-8");
templateResolver.setOrder(2);
templateResolver.setCheckExistence(true); /* FYI: necessary to chain TemplateResolvers */
templateResolver.setCacheable(false); /* FYI: during development -> false, so that we can see changes we make */
return templateResolver;
}
#Bean
public SpringTemplateEngine templateEngine() {
/* SpringTemplateEngine automatically applies SpringStandardDialect and
enables Spring's own MessageSource message resolution mechanisms. */
SpringTemplateEngine templateEngine = new SpringTemplateEngine();
templateEngine.addTemplateResolver(this.templateResolver());
templateEngine.addTemplateResolver(this.templateResolver2());
templateEngine.setEnableSpringELCompiler(true);
return templateEngine;
}
#Bean
public ViewResolver viewResolver() {
ThymeleafViewResolver viewResolver = new ThymeleafViewResolver();
viewResolver.setTemplateEngine(this.templateEngine());
viewResolver.setCharacterEncoding("UTF-8");
viewResolver.setCache(false); /* FYI: during development -> false */
viewResolver.setOrder(1);
return viewResolver;
}
}
I hope this will help others to save time and nerves^^.

If you are using Spring Boot, you can add an extra resolver on top of the default one like this:
First, add this to application.properties:
# This ensures that the default HTML template resolver of Thymeleaf has priority over our custom SVG resolver
spring.thymeleaf.template-resolver-order=0
Then add the extra resolver in a #Configuration class:
#Configuration
public class MyApplicationConfiguration {
#Bean
public ITemplateResolver svgTemplateResolver() {
SpringResourceTemplateResolver resolver = new SpringResourceTemplateResolver();
resolver.setPrefix("classpath:/templates/svg/");
resolver.setSuffix(".svg");
resolver.setTemplateMode("XML");
return resolver;
}
}
There is no need to manually define SpringTemplateEngine and ViewResolver beans.
You can disable caching during development using spring.thymeleaf.cache=false.

Spring Boot / Docker: Thymeleaf template not found for html mail

I have a problem with finding a thymeleaf template on docker. I'm familiar with the leading slash problem in ordinary controllers. However I'd now like to use thymeleaf to render email bodies.
My code looks like this:
#Component
public class HtmlEmailDocumenter implements Documenter {
#Autowired
SpringTemplateEngine thymeleafTemplateEngine;
// more dependencies
#Override
public void accept(Documentable documentable){
Context thymeleafContext = new Context();
thymeleafContext.setVariable("doc", documentable);
String template = "mail/default";
String htmlBody = thymeleafTemplateEngine.process(template, thymeleafContext);
// send the email...
}
}
The template in question is under /src/main/resources/templates/mail/default.html. I have alternatively tried using "mail/default.html" in the source code. Doesn't work either in docker.
Any hints welcome.

I am doing something similar in non-Boot Spring application by defining the template engine template and resolver as follows:
#Bean
public ResourceBundleMessageSource emailMessageSource() {
final ResourceBundleMessageSource messageSource = new ResourceBundleMessageSource();
messageSource.setBasename("templates/email/mailMessages");
return messageSource;
}
#Bean
public TemplateEngine emailTemplateEngine() {
final SpringTemplateEngine templateEngine = new SpringTemplateEngine();
templateEngine.addTemplateResolver(htmlTemplateResolver());
templateEngine.setTemplateEngineMessageSource(emailMessageSource());
return templateEngine;
}
private ITemplateResolver htmlTemplateResolver() {
final ClassLoaderTemplateResolver templateResolver = new ClassLoaderTemplateResolver();
templateResolver.setOrder(Integer.valueOf(2));
templateResolver.setPrefix("/templates/email/");
templateResolver.setSuffix(".html");
templateResolver.setTemplateMode(TemplateMode.HTML);
templateResolver.setCharacterEncoding("UTF-8");
templateResolver.setCacheable(false);
return templateResolver;
}
I then refer to an email message template using just the name of the template within the /templates/email directory without extension.

How do I enable Thymeleaf auto-reload with a custom resolver in Spring Boot?

I had to define a template resolver to get a custom dialect working, however this broke the auto-reloading of Thymeleaf templates. How can I re-enable this functionality? Alternatively, how do I add a custom dialect without having to define a template resolver?
#Configuration
public class ThymeleafConfig {
#Bean
public SpringTemplateEngine templateEngine(TagCacheService tagCacheService) {
SpringTemplateEngine templateEngine = new SpringTemplateEngine();
ClassLoaderTemplateResolver primaryResolver = new ClassLoaderTemplateResolver();
primaryResolver.setPrefix("templates/");
primaryResolver.setSuffix(".html");
primaryResolver.setTemplateMode(TemplateMode.HTML);
primaryResolver.setCharacterEncoding("UTF-8");
primaryResolver.setOrder(0);
primaryResolver.setCheckExistence(true);
templateEngine.addTemplateResolver(primaryResolver);
templateEngine.addDialect(new LayoutDialect());
templateEngine.addDialect(new SpringSecurityDialect());
templateEngine.addDialect(new MyDialect(tagCacheService));
return templateEngine;
}
}

I just checked the source code of org.springframework.boot.autoconfigure.thymeleaf.ThymeleafAutoConfiguration and I see that other dialects there are registered by just declaring an instance of the dialect as a bean. So maybe try that?
#Bean
public MyDialect myDialect(TagCacheService tagCacheService) {
return new MyDialect(tagCacheService);
}

To enable auto-reloading of templates on a custom template resolver, the set setCacheable property of the resolver to false. You can read this value from application properties to make it more versatile.
// Get value from config
#Value("${spring.thymeleaf.cache}")
private boolean enableCache;
#Bean
public SpringTemplateEngine templateEngine() {
SpringTemplateEngine templateEngine = new SpringTemplateEngine();
ClassLoaderTemplateResolver primaryResolver = new ClassLoaderTemplateResolver();
[ ... ]
primaryResolver.setCacheable(enableCache); // Set to false to enable reloading
[ ... ]
}

Spring Boot content-negotiation configuration

I have difficulties configuring content-negotiation with spring-boot.
I would like to keep most of the default spring-boot configuration.
I followed the following https://spring.io/blog/2013/05/11/content-negotiation-using-spring-mvc/
not so recent tutorial. At the moment when I send a request for application/json or txt/html the view doesn't seem to get resolved, but when I turn on #EnableWebMvc it does seem to get resolved.
Below is my current configuration.
#Configuration // according to the spring-boot docs this should be enough with spring-boot
//#EnableWebMvc If I enable this content-negotiation seems to work without any configuration, but I loose the default spring-boot configuration
public class MvcConfiguration implements WebMvcConfigurer {
#Bean(name = "jsonViewResolver")
public ViewResolver getJsonViewResolver() {
return new JsonViewResolver();
}
#Override
public void configureContentNegotiation(ContentNegotiationConfigurer configurer) {
// Simple strategy: only path extension is taken into account
configurer.favorPathExtension(true)
.defaultContentType(MediaType.TEXT_HTML)
.mediaType("html", MediaType.TEXT_HTML)
.mediaType("json", MediaType.APPLICATION_JSON);
}
#Bean
public ViewResolver contentNegotiatingViewResolver(ContentNegotiationManager manager) {
ContentNegotiatingViewResolver resolver = newContentNegotiatingViewResolver();
resolver.setContentNegotiationManager(manager);
return resolver;
}
}

You are not registering your resolvers in your content negotiation manager.
please try with the following modification:
#Bean
public ViewResolver contentNegotiatingViewResolver(ContentNegotiationManager manager){
ContentNegotiatingViewResolver resolver = newContentNegotiatingViewResolver();
resolver.setContentNegotiationManager(manager);
List<ViewResolver> resolvers = new ArrayList<>();
ViewResolver aViewResolver = getJsonViewResolver();
resolvers.add(aViewResolver);
resolver.setViewResolvers(resolvers);
return resolver;
}

Spring boot - cannot set default Locale

I am now developing Spring Boot application (only rest controllers). Each request to my server contains language tag. I would like to send response in specific language according to this tag. Controllers extract those tags from request and provide to service layer as a Locale instance. I have created properties file under src/main/resources, like this:
https://i.stack.imgur.com/fsXPG.jpg.
My problem is with default language. Regardless of provided Locale, messages returned from properties file are always from AppResources_pl.properties. I think that, problem is with default locale. For now i tryied two different ways and still don't know how to set default properties file to english.
First:
ResourceBundle myResources = ResourceBundle.getBundle("AppResources", currentLocale);
String message = myResources.getString("label.error");
Second:
#Bean
public LocaleResolver localeResolver() {
SessionLocaleResolver slr = new SessionLocaleResolver();
slr.setDefaultLocale(Locale.forLanguageTag("en-US"));
return slr;
}
#Bean
public MessageSource messageSource(){
ResourceBundleMessageSource messageSource = new ResourceBundleMessageSource();
messageSource.setBasename("AppResources");
messageSource.setDefaultEncoding("UTF-8");
return messageSource;
}
and in service:
messageSource.getMessage("label.error", null, locale)
Both way returning message but always from AppResources_pl.properties. How can i set AppResources.properties as a default properties file when provided locale is not found under *.properties files?

I found that in MessageSourceAccessor default locale is null, so used system locale. This issue appeared in the last versions because about 6 months ago I used provided in original comment configuration with LocaleResolver and it's worked fine.
Solved issue in following line return new MessageSourceAccessor(messageSource, Locale.US); (directly passed Locale)
#Bean(name = "messageSource")
public ReloadableResourceBundleMessageSource getMessageSource() {
final ReloadableResourceBundleMessageSource res = new ReloadableResourceBundleMessageSource();
res.setDefaultEncoding("UTF-8");
res.setFallbackToSystemLocale(false); // will force to use specified locale even if locale for current env is different
res.addBasenames("classpath:messages/validation", "classpath:messages/messages", "classpath:messages/titles");
return res;
}
#Bean
public MessageSourceAccessor getMessageSourceAccessor(final MessageSource messageSource) {
return new MessageSourceAccessor(messageSource, Locale.US);
}

You can try below:
/*
* Create MessageSource bean
*/
#Bean
public MessageSource messageSource() {
ReloadableResourceBundleMessageSource messageSource = new
ReloadableResourceBundleMessageSource();
messageSource.setBasename("classpath:AppResources");
messageSource.setDefaultEncoding("UTF-8");
return messageSource;
}
/*
* Create LocaleResolver Bean
*/
#Bean
public LocaleResolver localeResolver(){
CookieLocaleResolver resolver = new CookieLocaleResolver();
resolver.setDefaultLocale(new Locale("en")); // your default locale
return resolver;
}