Spring 是否应制作someRestController，以便与LocalResolver一起接收i18n的lang参数？

我正在开发Spring Boot应用程序，我需要使用i18n。我看了很多教程，并实现了新的类LocaleConfiguration

@Configuration
public class LocaleConfiguration implements WebMvcConfigurer {

  /**
   * * @return default Locale set by the user
   */
  @Bean(name = "localeResolver")
  public LocaleResolver localeResolver() {
    SessionLocaleResolver slr = new SessionLocaleResolver();
    slr.setDefaultLocale(Locale.US);
    return slr;
  }

  /**
   * an interceptor bean that will switch to a new locale based on the value of the language parameter appended to a request:
   *
   * @param registry
   * @language should be the name of the request param i.e  localhost:8010/api/get-greeting?language=fr
   * <p>
   * Note: All requests to the backend needing Internationalization should have the "language" request param
   */
  @Override
  public void addInterceptors(InterceptorRegistry registry) {
    LocaleChangeInterceptor localeChangeInterceptor = new LocaleChangeInterceptor();
    localeChangeInterceptor.setParamName("lang");
    registry.addInterceptor(localeChangeInterceptor);
  }
}

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所以我的问题是，我需要制作新的控制器来处理这个问题，还是由LocalResolver类自动完成？

我会回答你的问题，第一个答案是LocalResolver！ 因为您有LocaleSolver Bean，并添加了localeChangeInterceptor，其类层次结构是

LocaleChangeInterceptor是一个拦截器。从源代码可知，它是在请求到达RequestMapping之前执行的。它的作用只是从请求中获取请求参数（默认为locale），然后在LocaleResolver中设置当前的locale

源代码：

@Override
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
        throws ServletException {
    //Note here
    **String newLocale = request.getParameter(getParamName());**
    if (newLocale != null) {
        if (checkHttpMethod(request.getMethod())) {
            LocaleResolver localeResolver = RequestContextUtils.getLocaleResolver(request);
            if (localeResolver == null) {
                throw new IllegalStateException(
                        "No LocaleResolver found: not in a DispatcherServlet request?");
            }
            try {
                localeResolver.setLocale(request, response, parseLocaleValue(newLocale));
            }
            catch (IllegalArgumentException ex) {
                if (isIgnoreInvalidLocale()) {
                    logger.debug("Ignoring invalid locale value [" + newLocale + "]: " + ex.getMessage());
                }
                else {
                    throw ex;
                }
            }
        }
    }
    // Proceed in any case.
    return true;
}

看，我不得不发表评论

String newLocale = request.getParameter(getParamName());

转移

/**
 * Return the name of the parameter that contains a locale specification
 * in a locale change request.
 */
public String getParamName() {
    return this.paramName;
}

其中，这个.paramName是

---

你懂吗

我懂，谢谢！但是，当用户想要更改语言时，开发人员将在什么APIaddress上向我发送param lang？直接添加到url。例如：https://{url}？lang=en_us，来自FE的传入参数，API不变

/**
 * Return the name of the parameter that contains a locale specification
 * in a locale change request.
 */
public String getParamName() {
    return this.paramName;
}

/**
 * Default name of the locale specification parameter: "locale".
 */
public static final String DEFAULT_PARAM_NAME = "locale";