In Spring Boot and Kotlin how can you properly add internationalization? - spring

Question

I have been following this tutorial and I can follow it, although I had some issues.
Almost at the end, where it talks about configuration properties, I though it was a good idea to try to set some kind of internationalization to it, with a different file depending on the language, but I have been unable to do so. I only load it on English, no matter how I try.

Answer 1

Have you read the Spring Boot Docs on Internationalization? I guess it is not that helpful.
Suppose you have your resource bundle like this.
- src/main/resources/
- messages.properties
- messages_es.properties
- ...
You need to add some configuration:
#Configuration
class AppConfig : WebMvcConfigurer {
#Bean
fun localeResolver() = SessionLocaleResolver().apply {
setDefaultLocale(Locale.ENGLISH)
}
#Bean
fun localeInterceptor() = LocaleChangeInterceptor().apply {
this.paramName = "lang"
}
override fun addInterceptors(registry: InterceptorRegistry) {
registry.addInterceptor(localeInterceptor())
}
}
Then an example using greet.hello might look like:
import org.springframework.context.MessageSource
import org.springframework.context.i18n.LocaleContextHolder
import org.springframework.web.bind.annotation.GetMapping
import org.springframework.web.bind.annotation.RestController
#RestController
class PageController(val messageSource: MessageSource) {
#GetMapping("/greet")
fun greet(): String {
return messageSource.getMessage("greet.hello", null, LocaleContextHolder.getLocale())
}
}
If you do not think this looks pretty, then try using some of Kotlin's features to clean it up.
This is how to choose a language:
# Use the default
curl --request GET --url 'http://localhost:8080/greet'
# Hello
# Use English
curl --request GET --url 'http://localhost:8080/greet?lang=en'
# Hello
# Use Spanish
curl --request GET --url 'http://localhost:8080/greet?lang=es'
# Hola