SpringBoot2로 Rest api 만들기(7) – MessageSource를 이용한 Exception 처리

src/main/java/com/rest/api/config/MessageConfiguration.java

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+package com.rest.api.config;
+
+import lombok.extern.slf4j.Slf4j;
+import net.rakugakibox.util.YamlResourceBundle;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.context.MessageSource;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.context.support.ResourceBundleMessageSource;
+import org.springframework.web.servlet.LocaleResolver;
+import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
+import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
+import org.springframework.web.servlet.i18n.LocaleChangeInterceptor;
+import org.springframework.web.servlet.i18n.SessionLocaleResolver;
+
+import java.util.Locale;
+import java.util.MissingResourceException;
+import java.util.ResourceBundle;
+
+@Configuration
+public class MessageConfiguration implements WebMvcConfigurer {
+
+    @Bean // 세션에 지역설정. default는 KOREAN = 'ko'
+    public LocaleResolver localeResolver() {
+        SessionLocaleResolver slr = new SessionLocaleResolver();
+        slr.setDefaultLocale(Locale.KOREAN);
+        return slr;
+    }
+
+    @Bean // 지역설정을 변경하는 인터셉터. 요청시 파라미터에 lang 정보를 지정하면 언어가 변경됨.
+    private LocaleChangeInterceptor localeChangeInterceptor() {
+        LocaleChangeInterceptor lci = new LocaleChangeInterceptor();
+        lci.setParamName("lang");
+        return lci;
+    }
+
+    @Override // 인터셉터를 시스템 레지스트리에 등록
+    public void addInterceptors(InterceptorRegistry registry) {
+        registry.addInterceptor(localeChangeInterceptor());
+    }
+
+    @Bean // yml 파일을 참조하는 MessageSource 선언
+    public MessageSource messageSource(
+            @Value("${spring.messages.basename}") String basename,
+            @Value("${spring.messages.encoding}") String encoding
+    ) {
+        YamlMessageSource ms = new YamlMessageSource();
+        ms.setBasename(basename);
+        ms.setDefaultEncoding(encoding);
+        ms.setAlwaysUseMessageFormat(true);
+        ms.setUseCodeAsDefaultMessage(true);
+        ms.setFallbackToSystemLocale(true);
+        return ms;
+    }
+
+    // locale 정보에 따라 다른 yml 파일을 읽도록 처리
+    private static class YamlMessageSource extends ResourceBundleMessageSource {
+        @Override
+        protected ResourceBundle doGetBundle(String basename, Locale locale) throws MissingResourceException {
+            return ResourceBundle.getBundle(basename, locale, YamlResourceBundle.Control.INSTANCE);
+        }
+    }
+}