Spring Boot和Freemarker国际化无法在电子邮件中起作用

Question

我正在使用Spring Boot（2.5.2）和FreeMarker将电子邮件发送给用户。它在没有添加任何国际化支持的情况下工作正常，但是我今天尝试添加它，但它不起作用。由于某种原因，Spring.ftl抱怨它无法在我的消息中找到属性。

以下是我的配置文件

@Configuration
public class CommonConfiguration implements WebMvcConfigurer {

    @Bean
    public LocaleResolver localeResolver() {
        AcceptHeaderLocaleResolver localeResolver = new AcceptHeaderLocaleResolver();
        localeResolver.setDefaultLocale(Locale.US);
        return localeResolver;
    }

    @Override
    public void addInterceptors(final InterceptorRegistry registry) {
        final LocaleChangeInterceptor localeChangeInterceptor = new LocaleChangeInterceptor();
        localeChangeInterceptor.setParamName("lang");
        registry.addInterceptor(localeChangeInterceptor);
    }

    @Bean(name = "messageSource")
    public MessageSource messageSource() {
        ReloadableResourceBundleMessageSource ms = new ReloadableResourceBundleMessageSource();
        ms.setBasenames("classpath:i18n/messages");
        ms.setDefaultEncoding("UTF-8");
        ms.setCacheSeconds(3600);
        return ms;
    }

}

application.yml file（对于春季freemarker设置）

spring:
  profiles:
    active: dev
  autoconfigure:
    exclude: org.springframework.boot.autoconfigure.security.servlet.SecurityAutoConfiguration
  freemarker:
    settings:
      auto_import: /spring.ftl as spring

我的邮件.ftl文件，此行引起了问题

<@spring.message "email.common.logo.alt.txt"/>

我已经验证了此文本是否存在当我使用 messagesource.getMessage（“ email.common.logo.alt.txt”，null，localecontextholder.getlocale（））在我的Java代码中时，我可以访问相应的值。

错误日志

2022-06-03 16:08:48.590 ERROR 67685 --- [         task-2] f.runtime                                : Error executing FreeMarker template

freemarker.core.InvalidReferenceException: The following has evaluated to null or missing:
==> springMacroRequestContext  [in template "spring.ftl" at line 28, column 24]

----
Tip: If the failing expression is known to legally refer to something that's sometimes null or missing, either specify a default value like myOptionalVar!myDefault, or use <#if myOptionalVar??>when-present<#else>when-missing</#if>. (These only cover the last step of the expression; to cover the whole expression, use parenthesis: (myOptionalVar.foo)!myDefault, (myOptionalVar.foo)??
----

----
FTL stack trace ("~" means nesting-related):
    - Failed at: ${springMacroRequestContext.getMessag...  [in template "spring.ftl" in macro "message" at line 28, column 22]
    - Reached through: @spring.message "email.common.logo.al...  [in template "emails/layout/email-header.ftl" at line 3, column 109]
    - Reached through: #include "email-header.ftl"  [in template "emails/layout/email-layout.ftl" in macro "generalEmailLayout" at line 72, column 8]
    - Reached through: @layout.generalEmailLayout headInclud...  [in template "emails/user-management/mail.ftl" at line 2, column 1]
----
    at freemarker.core.InvalidReferenceException.getInstance(InvalidReferenceException.java:134) ~[freemarker-2.3.31.jar:2.3.31]
    at freemarker.core.UnexpectedTypeException.newDescriptionBuilder(UnexpectedTypeException.java:85) ~[freemarker-2.3.31.jar:2.3.31]
    at freemarker.core.UnexpectedTypeException.<init>(UnexpectedTypeException.java:48) ~[freemarker-2.3.31.jar:2.3.31]
    at freemarker.core.NonHashException.<init>(NonHashException.java:49) ~[freemarker-2.3.31.jar:2.3.31]
    at freemarker.core.Dot._eval(Dot.java:48) ~[freemarker-2.3.31.jar:2.3.31]
    at freemarker.core.Expression.eval(Expression.java:101) ~[freemarker-2.3.31.jar:2.3.31]
    at freemarker.core.MethodCall._eval(MethodCall.java:55) ~[freemarker-2.3.31.jar:2.3.31]
    at freemarker.core.Expression.eval(Expression.java:101) ~[freemarker-2.3.31.jar:2.3.31]
    at freemarker.core.BuiltInsForOutputFormatRelated$AbstractConverterBI.calculateResult(BuiltInsForOutputFormatRelated.java:50) ~[freemarker-2.3.31.jar:2.3.31]
    at freemarker.core.MarkupOutputFormatBoundBuiltIn._eval(MarkupOutputFormatBoundBuiltIn.java:40) ~[freemarker-2.3.31.jar:2.3.31]
    at freemarker.core.Expression.eval(Expression.java:101) ~[freemarker-2.3.31.jar:2.3.31]
    at freemarker.core.DollarVariable.calculateInterpolatedStringOrMarkup(DollarVariable.java:100) ~[freemarker-2.3.31.jar:2.3.31]
    at freemarker.core.DollarVariable.accept(DollarVariable.java:63) ~[freemarker-2.3.31.jar:2.3.31]
    at freemarker.core.Environment.visit(Environment.java:383) ~[freemarker-2.3.31.jar:2.3.31]
    at freemarker.core.Environment.invokeMacroOrFunctionCommonPart(Environment.java:889) ~[freemarker-2.3.31.jar:2.3.31]
    at freemarker.core.Environment.invokeMacro(Environment.java:825) ~[freemarker-2.3.31.jar:2.3.31]
    at freemarker.core.UnifiedCall.accept(UnifiedCall.java:84) ~[freemarker-2.3.31.jar:2.3.31]
    at freemarker.core.Environment.visit(Environment.java:347) ~[freemarker-2.3.31.jar:2.3.31]
    at freemarker.core.Environment.visit(Environment.java:353) ~[freemarker-2.3.31.jar:2.3.31]
    at freemarker.core.Environment.include(Environment.java:2955) ~[freemarker-2.3.31.jar:2.3.31]
    at freemarker.core.Include.accept(Include.java:171) ~[freemarker-2.3.31.jar:2.3.31]
    at freemarker.core.Environment.visit(Environment.java:383) ~[freemarker-2.3.31.jar:2.3.31]
    at freemarker.core.Environment.invokeMacroOrFunctionCommonPart(Environment.java:889) ~[freemarker-2.3.31.jar:2.3.31]
    at freemarker.core.Environment.invokeMacro(Environment.java:825) ~[freemarker-2.3.31.jar:2.3.31]
    at freemarker.core.UnifiedCall.accept(UnifiedCall.java:84) ~[freemarker-2.3.31.jar:2.3.31]