How to configure i18n in Spring boot 2 + Webflux + Thymeleaf?

Question

I just start a new project based on Spring boot 2 + Webflux. On upgrading version of spring boot and replace spring-boot-starter-web with spring-boot-starter-

Answer 1

With spring-boot-starter-webflux, there are

• DelegatingWebFluxConfiguration
• LocaleContextResolver

For example, to use a query parameter "lang" to explicitly control the locale:

1. Implement LocaleContextResolver, so that resolveLocaleContext() returns a SimpleLocaleContext determined by a GET parameter of "lang". I name this implementation QueryParamLocaleContextResolver. Note that the default LocaleContextResolver is an org.springframework.web.server.i18n.AcceptHeaderLocaleContextResolver.

2. Create a @Configuration class that extends DelegatingWebFluxConfiguration. Override DelegatingWebFluxConfiguration.localeContextResolver() to return QueryParamLocaleContextResolver that we just created in step 1. Name this configuration class WebConfig.

3. In WebConfig, override DelegatingWebFluxConfiguration.configureViewResolvers() and add the ThymeleafReactiveViewResolver bean as a view resolver. We do this because, for some reason, DelegatingWebFluxConfiguration will miss ThymeleafReactiveViewResolver after step 2.

Also, I have to mention that, to use i18n with the reactive stack, this bean is necessary:

    @Bean
    public MessageSource messageSource() {
        final ReloadableResourceBundleMessageSource messageSource = new ReloadableResourceBundleMessageSource();
        messageSource.setBasenames("classpath:/messages");
        messageSource.setUseCodeAsDefaultMessage(true);
        messageSource.setDefaultEncoding("UTF-8");
        messageSource.setCacheSeconds(5);
        return messageSource;
}

After creating a natural template, some properties files, and a controller, you will see that:

• localhost:8080/test?lang=zh gives you the Chinese version

• localhost:8080/test?lang=en gives you the English version

Just don't forget in , otherwise you may see some nasty display of Chinese characters.