我的API使用Jersey 2，现在我想支持国际化。我理解我的客户端应该指定Accept-Language参数，但我想了解如何正确处理它。
我们假设我的API应该只处理FRENCH和ENGLISH种语言。我知道我可以使用以下代码检索首选区域设置：
@GET
@Path("a-path")
public Response doSomething(@Context HttpServletRequest request) {
Locale locale = request.getLocale();
// ...
}
问题在于我的API不支持首选区域设置。让我们说我的客户根据w3c发送给我Accept-Language: da, en-gb;q=0.8, en;q=0.7，它基本上意味着："I prefer Danish, but will accept British English and other types of English."。由于首选语言环境只返回最期望的语言环境，有没有办法通过我的API选择第一个支持的语言？我想在一个地方（即Filters）而不是每个资源处理它。
答案 0 :(得分：3)
获取语言环境的一个方法是使用HttpHeaders#getAcceptableLanguages()。
获取响应可接受的语言列表。
如果未指定可接受的语言，则返回包含单个通配符Locale实例的只读列表（语言字段设置为＆＃34; *＆＃34;）。
<强>返回： 可读语言的只读列表，根据其q值排序，首先是最高优先级。
您可以使用HttpHeaders
@Context
public Response doSomething(@Context HttpHeaders headers) {
List<Locale> langs = headers.getAcceptableLanguages();
如果您想在filter中获取列表，还可以从ContainerRequestContext
@Override
public void filter(ContainerRequestContext requestContext) throw .. {
List<Locales> langs = requestContext.getAcceptableLanguages();
}
如果您想在资源方法中使用Locale，但又不想做所有语言环境＆＃34;解析＆＃34;在该方法中，您可以使用一些依赖注入，并创建一个Factory，您可以在其中注入HttpHeaders并解析那里的区域设置
另请参阅： Dependency injection with Jersey 2.0
下面是一个完整的测试用例示例，它使用了我提到的关于在Factory上使用过滤器和依赖项注入的最后两点的组合，以便您可以将已解析的Locale注入资源方法。该示例使用仅允许英语的虚拟区域设置解析程序。在我们解析了语言环境之后，我们将其设置为请求上下文属性，并从Factory内部进行检索，以便我们可以将其注入资源方法
@GET
public String get(@Context Locale locale) {
return locale.toString();
}
另请参阅： How to inject an object into jersey request context?
如果您还有其他任何想要我解释的示例
，请告诉我import java.io.IOException;
import java.util.List;
import java.util.Locale;
import java.util.logging.Logger;
import javax.inject.Inject;
import javax.inject.Singleton;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.container.ContainerRequestContext;
import javax.ws.rs.container.ContainerRequestFilter;
import javax.ws.rs.container.PreMatching;
import javax.ws.rs.core.Context;
import javax.ws.rs.core.Response;
import javax.ws.rs.ext.Provider;
import org.glassfish.hk2.api.Factory;
import org.glassfish.hk2.utilities.binding.AbstractBinder;
import org.glassfish.jersey.filter.LoggingFilter;
import org.glassfish.jersey.process.internal.RequestScoped;
import org.glassfish.jersey.server.ResourceConfig;
import org.glassfish.jersey.test.JerseyTest;
import org.junit.Test;
import static org.hamcrest.CoreMatchers.is;
import static org.junit.Assert.assertThat;
/**
* Stack Overflow question https://stackoverflow.com/q/36871274/2587435
*
* Run this like any other JUnit test. Only one required test dependency:
*
* <dependency>
* <groupId>org.glassfish.jersey.test-framework.providers</groupId>
* <artifactId>jersey-test-framework-provider-inmemory</artifactId>
* <version>${jersey2.version}</version>
* </dependency>
*
* @author Paul Samsotha
*/
public class AcceptLanguageTest extends JerseyTest {
@Path("language")
public static class TestResource {
@GET
public String get(@Context Locale locale) {
return locale.toString();
}
}
public static interface LocaleResolver {
Locale resolveLocale(List<Locale> locales);
}
// Note: if you look in the javadoc for getAcceptableLanguages()
// you will notice that it says if there is not acceptable language
// specified, that there is a default single wildcard (*) locale.
// So this implementation sucks, as it doesn't check for that.
// You will want to make sure to do so!
public static class DefaultLocaleResolver implements LocaleResolver {
@Override
public Locale resolveLocale(List<Locale> locales) {
if (locales.contains(Locale.ENGLISH)) {
return Locale.ENGLISH;
}
return null;
}
}
@Provider
@PreMatching
public static class LocaleResolverFilter implements ContainerRequestFilter {
static final String LOCALE_PROPERTY = "LocaleResolverFilter.localProperty";
@Inject
private LocaleResolver localeResolver;
@Override
public void filter(ContainerRequestContext context) throws IOException {
List<Locale> locales = context.getAcceptableLanguages();
Locale locale = localeResolver.resolveLocale(locales);
if (locale == null) {
context.abortWith(Response.status(Response.Status.NOT_ACCEPTABLE).build());
return;
}
context.setProperty(LOCALE_PROPERTY, locale);
}
}
public static class LocaleFactory implements Factory<Locale> {
@Context
private ContainerRequestContext context;
@Override
public Locale provide() {
return (Locale) context.getProperty(LocaleResolverFilter.LOCALE_PROPERTY);
}
@Override
public void dispose(Locale l) {}
}
@Override
public ResourceConfig configure() {
return new ResourceConfig(TestResource.class)
.register(LocaleResolverFilter.class)
.register(new AbstractBinder() {
@Override
protected void configure() {
bindFactory(LocaleFactory.class)
.to(Locale.class).in(RequestScoped.class);
bind(DefaultLocaleResolver.class)
.to(LocaleResolver.class).in(Singleton.class);
}
})
.register(new LoggingFilter(Logger.getAnonymousLogger(), true));
}
@Test
public void shouldReturnEnglish() {
final String accept = "da, en-gb;q=0.8, en;q=0.7";
final Response response = target("language").request()
.acceptLanguage(accept)
.get();
assertThat(response.readEntity(String.class), is("en"));
}
@Test
public void shouldReturnNotAcceptable() {
final String accept = "da";
final Response response = target("language").request()
.acceptLanguage(accept)
.get();
assertThat(response.getStatus(), is(Response.Status.NOT_ACCEPTABLE.getStatusCode()));
}
}
答案 1 :(得分：0)
JAX-RS API允许您使用Request.selectVariant（List）方法选择语言环境。
在REST处理程序或CDI bean中尝试以下代码：
import javax.ws.rs.core.Variant;
import javax.ws.rs.core.Request;
@Context
private Request req;
private Locale getResponseLocale(boolean throwIfNoneMatch) throws NotAcceptableException{
// Put your supported languages here
List<Variant> langVariants = Variant.languages(
new Locale("da"),
new Locale("en-gb"),
Locale.getDefault()).build();
Locale locale = Locale.getDefault();
Variant selectVariant = this.req.selectVariant(langVariants);
if (selectVariant != null) {
locale = selectVariant.getLanguage();
} else if (throwIfNoneMatch) {
throw new NotAcceptableException(Response.notAcceptable(langVariants).build());
}
return locale;
}