Springboot locale with Rest request and Thymeleaf - spring-boot

Question

So another application directs user to my server. The redirect is Post request (application/json) with value language in the JSON. How should I set the locale value in RestController? So that Thymeleaf could render the correct text.
Setting locale with LocaleContextHolder doesn't do the trick.

Answer 1

You should follow this guide here since Internationalization is a common task in spring-boot. In case if you need a short answer:
First configure a LocaleResolver in your Application.java:
#Bean(name = "localeResolver")
public LocaleResolver localeResolver() {
SessionLocaleResolver slr = new SessionLocaleResolver();
slr.setDefaultLocale(new Locale("tr", "TR"));
return slr;
}
Then again in your Application.java file configure a LocaleChangeInterceptor:
#Bean(name = "localeChangeInterceptor")
public LocaleChangeInterceptor localeChangeInterceptor() {
LocaleChangeInterceptor lci = new LocaleChangeInterceptor();
lci.setParamName("lang");
return lci;
}
And finally register your LocaleChangeInterceptor (also in Application.java):
#Override
public void addInterceptors(InterceptorRegistry registry) {
registry.addInterceptor(localeChangeInterceptor());
}
Now if you send a request parameter named "lang" with your POST request spring will use its value to determine the desired locale and change it accordingly.

Answer 2

Ended up with the following solution:
WebMvcConfigurer has these
#Bean
public LocaleResolver localeResolver() {
SessionLocaleResolver r = new SessionLocaleResolver();
r.setDefaultLocale(new Locale("jp"));
return r;
}
And in the controller I call this classes public method:
#Component
public class WebLanguage {
public void setLocale(HttpServletRequest request, HttpServletResponse response) {
if (!request.getParameterMap().containsKey("lang")) return;
LocaleResolver localeResolver = localeResolver(request);
localeResolver.setLocale(request, response, new Locale(request.getParameterMap().get("lang")[0]));
}
LocaleResolver localeResolver(HttpServletRequest request) {
return RequestContextUtils.getLocaleResolver(request);
}
}