Question

我刚刚开始一个基于Spring boot 2 + Webflux的新项目。在升级spring boot版本时，将spring-boot-starter-web替换为spring-boot-starter-webflux类，如

WebMvcConfigurerAdapter
LocaleResolver
LocaleChangeInterceptor

缺少。我现在怎样才能配置defaultLocale和拦截器来改变语言？

Answer 1

只需添加WebFilter即可从查询参数的值设置Accept-Language标头。以下示例从http://localhost:8080/examples?language=es等URI上的语言查询参数中获取语言：

import org.springframework.boot.context.event.ApplicationReadyEvent;
import org.springframework.context.ApplicationContext;
import org.springframework.context.event.EventListener;
import org.springframework.http.server.reactive.ServerHttpRequest;
import org.springframework.stereotype.Component;
import org.springframework.util.MultiValueMap;
import org.springframework.web.server.ServerWebExchange;
import org.springframework.web.server.WebFilter;
import org.springframework.web.server.WebFilterChain;
import org.springframework.web.server.adapter.DefaultServerWebExchange;
import org.springframework.web.server.adapter.HttpWebHandlerAdapter;
import reactor.core.publisher.Mono;

import static org.springframework.util.StringUtils.isEmpty;

@Component
public class LanguageQueryParameterWebFilter implements WebFilter {

    private final ApplicationContext applicationContext;

    private HttpWebHandlerAdapter httpWebHandlerAdapter;

    public LanguageQueryParameterWebFilter(final ApplicationContext applicationContext) {
        this.applicationContext = applicationContext;
    }

    @EventListener(ApplicationReadyEvent.class)
    public void loadHttpHandler() {
        this.httpWebHandlerAdapter = applicationContext.getBean(HttpWebHandlerAdapter.class);
    }

    @Override
    public Mono<Void> filter(final ServerWebExchange exchange, final WebFilterChain chain) {
        final ServerHttpRequest request = exchange.getRequest();
        final MultiValueMap<String, String> queryParams = request.getQueryParams();
        final String languageValue = queryParams.getFirst("language");

        final ServerWebExchange localizedExchange = getServerWebExchange(languageValue, exchange);
        return chain.filter(localizedExchange);
    }

    private ServerWebExchange getServerWebExchange(final String languageValue, final ServerWebExchange exchange) {
        return isEmpty(languageValue)
                ? exchange
                : getLocalizedServerWebExchange(languageValue, exchange);
    }

    private ServerWebExchange getLocalizedServerWebExchange(final String languageValue, final ServerWebExchange exchange) {
        final ServerHttpRequest httpRequest = exchange.getRequest()
                .mutate()
                .headers(httpHeaders -> httpHeaders.set("Accept-Language", languageValue))
                .build();

        return new DefaultServerWebExchange(httpRequest, exchange.getResponse(),
                httpWebHandlerAdapter.getSessionManager(), httpWebHandlerAdapter.getCodecConfigurer(),
                httpWebHandlerAdapter.getLocaleContextResolver());
    }
}

它使用@EventListener(ApplicationReadyEvent.class)以避免循环依赖。

随意测试并提供有关此POC的反馈。

Answer 2

使用spring-boot-starter-webflux，有

DelegatingWebFluxConfiguration
LocaleContextResolver

例如，要使用查询参数“lang”显式控制语言，您可以执行以下操作：

实现LocaleContextResolver，以便 resolveLocaleContext（）返回由“lang”值确定的SimpleLocaleContext。我将此实现命名为QueryParamLocaleContextResolver。请注意，默认的LocaleContextResolver是org.springframework.web.server.i18n.AcceptHeaderLocaleContextResolver。
创建一个扩展DelegatingWebFluxConfiguration的@Configuration类。覆盖DelegatingWebFluxConfiguration.localeContextResolver（）以返回我们刚刚在步骤1中创建的QueryParamLocaleContextResolver。将此配置类命名为WebConfig。
在WebConfig中，覆盖DelegatingWebFluxConfiguration.configureViewResolvers（）并将ThymeleafReactiveViewResolver bean添加为视图解析器。我们这样做是因为，出于某种原因，DelegatingWebFluxConfiguration将在第2步之后错过ThymeleafReactiveViewResolver。我们只需修复它。

另外，我必须提一下，要将i18n与反应堆栈一起使用，这个bean是必要的：

    @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;
}

创建自然模板，一些属性文件和控制器后，您应该实现：

localhost：8080 / test？lang = zh给你中文版

localhost：8080 / test？lang = zh-CN为您提供英文版

请不要忘记<meta charset="UTF-8">中的<head>，否则您可能会看到一些令人讨厌的汉字显示。

Answer 3

使用Spring Boot Starter Web磁通的另一种解决方案更加简洁，它是使用HttpHandler定义自己的WebHttpHandlerBuilder，您可以在其中设置LocaleContextResolver。

文档（请参阅1.2.2 WebHandler API）：https://docs.spring.io/spring/docs/current/spring-framework-reference/web-reactive.html#webflux-config-customize

MyLocaleContextResolver.java

public class MyLocaleContextResolver implements LocaleContextResolver {


    @Override
    public LocaleContext resolveLocaleContext(ServerWebExchange exchange) {      
        return new SimpleLocaleContext(Locale.FRENCH);        
    }

    @Override
    public void setLocaleContext(ServerWebExchange exchange, LocaleContext localeContext) {
        throw new UnsupportedOperationException();
    }
}

然后在配置文件（带有@Configuration注释）或您的spring boot应用程序文件中，定义您自己的HttpHandler bean。

Application.java

@SpringBootApplication
public class Application {

    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }

    @Bean
    public HttpHandler httpHandler(ApplicationContext context) {

        MyLocaleContextResolver localeContextResolver = new MyLocaleContextResolver();

        return WebHttpHandlerBuilder.applicationContext(context)
                .localeContextResolver(localeContextResolver) // set your own locale resolver
                .build();

    }

}

就是这样！

如何在Spring boot 2 + Webflux + Thymeleaf中配置i18n？

3 个答案: