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

build.gradle

@@ -25,6 +25,7 @@ dependencies {
     implementation 'org.springframework.boot:spring-boot-starter-web'
     implementation 'io.springfox:springfox-swagger2:2.6.1'
     implementation 'io.springfox:springfox-swagger-ui:2.6.1'
+    implementation 'net.rakugakibox.util:yaml-resource-bundle:1.1'
     compileOnly 'org.projectlombok:lombok'
     runtimeOnly 'com.h2database:h2'
     runtimeOnly 'mysql:mysql-connector-java'

src/main/java/com/rest/api/advice/ExceptionAdvice.java

@@ -4,6 +4,8 @@ import com.rest.api.advice.exception.CUserNotFoundException;
 import com.rest.api.model.response.CommonResult;
 import com.rest.api.service.ResponseService;
 import lombok.RequiredArgsConstructor;
+import org.springframework.context.MessageSource;
+import org.springframework.context.i18n.LocaleContextHolder;
 import org.springframework.http.HttpStatus;
 import org.springframework.web.bind.annotation.ExceptionHandler;
 import org.springframework.web.bind.annotation.ResponseStatus;
@@ -17,15 +19,25 @@ public class ExceptionAdvice {
 
     private final ResponseService responseService;
 
-//    @ExceptionHandler(Exception.class)
-//    @ResponseStatus(HttpStatus.INTERNAL_SERVER_ERROR)
-//    protected CommonResult defaultException(HttpServletRequest request, Exception e) {
-//        return responseService.getFailResult();
-//    }
+    private final MessageSource messageSource;
+
+    @ExceptionHandler(Exception.class)
+    @ResponseStatus(HttpStatus.INTERNAL_SERVER_ERROR)
+    protected CommonResult defaultException(HttpServletRequest request, Exception e) {
+        return responseService.getFailResult(Integer.valueOf(getMessage("unKnown.code")), getMessage("unKnown.msg"));
+    }
 
     @ExceptionHandler(CUserNotFoundException.class)
     @ResponseStatus(HttpStatus.INTERNAL_SERVER_ERROR)
     protected CommonResult userNotFoundException(HttpServletRequest request, CUserNotFoundException e) {
-        return responseService.getFailResult();
+        return responseService.getFailResult(Integer.valueOf(getMessage("userNotFound.code")), getMessage("userNotFound.msg"));
+    }
+
+    private String getMessage(String code) {
+        return getMessage(code, null);
+    }
+
+    private String getMessage(String code, Object[] args) {
+        return messageSource.getMessage(code, args, LocaleContextHolder.getLocale());
     }
 }

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

@@ -0,0 +1,63 @@
+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);
+        }
+    }
+}

src/main/java/com/rest/api/controller/v1/UserController.java

@@ -13,6 +13,8 @@ import io.swagger.annotations.ApiParam;
 import lombok.RequiredArgsConstructor;
 import org.springframework.web.bind.annotation.*;
 
+import java.util.Locale;
+
 @Api(tags = {"1. User"})
 @RequiredArgsConstructor
 @RestController
@@ -31,9 +33,9 @@ public class UserController {
 
     @ApiOperation(value = "회원 단건 조회", notes = "userId로 회원을 조회한다")
     @GetMapping(value = "/user/{userId}")
-    public BasicResult<User> findUserById(@ApiParam(value = "회원ID", required = true) @RequestParam int userId) {
+    public BasicResult<User> findUserById(@ApiParam(value = "회원ID", required = true) @PathVariable int userId,
+                                          @ApiParam(value = "언어", defaultValue = "ko") @RequestParam String lang) {
         // 결과데이터가 단일건인경우 getBasicResult를 이용해서 결과를 출력한다.
-//        return responseService.getBasicResult(userJpaRepo.findById(userId).orElse(null));
         return responseService.getBasicResult(userJpaRepo.findById(userId).orElseThrow(CUserNotFoundException::new));
     }
 
@@ -63,7 +65,7 @@ public class UserController {
     @ApiOperation(value = "회원 삭제", notes = "userId로 회원정보를 삭제한다")
     @DeleteMapping(value = "/user/{userId}")
     public CommonResult delete(
-            @ApiParam(value = "회원ID", required = true) @RequestParam int userId) {
+            @ApiParam(value = "회원ID", required = true) @PathVariable int userId) {
         userJpaRepo.deleteById(userId);
         // 성공 결과 정보만 필요한경우 getSuccessResult()를 이용하여 결과를 출력한다.
         return responseService.getSuccessResult();

src/main/java/com/rest/api/service/ResponseService.java

@@ -52,11 +52,11 @@ public class ResponseService {
         return result;
     }
     // 실패 결과만 처리하는 메소드
-    public CommonResult getFailResult() {
+    public CommonResult getFailResult(int code, String msg) {
         CommonResult result = new CommonResult();
         result.setSuccess(false);
-        result.setCode(CommonResponse.FAIL.getCode());
-        result.setMsg(CommonResponse.FAIL.getMsg());
+        result.setCode(code);
+        result.setMsg(msg);
         return result;
     }
     // 결과 모델에 api 요청 성공 데이터를 세팅해주는 메소드

src/main/resources/application.yml

@@ -9,4 +9,7 @@ spring:
   jpa:
     database-platform: org.hibernate.dialect.H2Dialect
     #properties.hibernate.hbm2ddl.auto: none
-    showSql: true
+    showSql: true
+  messages:
+    basename: i18n/exception
+    encoding: UTF-8

src/main/resources/i18n/exception_en.yml

@@ -0,0 +1,6 @@
+unKnown:
+  code: "-9999"
+  msg: "An unknown error has occurred."
+userNotFound:
+  code: "-1000"
+  msg: "This member not exist"

src/main/resources/i18n/exception_ko.yml

@@ -0,0 +1,6 @@
+unKnown:
+  code: "-9999"
+  msg: "알수 없는 오류가 발생하였습니다."
+userNotFound:
+  code: "-1000"
+  msg: "존재하지 않는 회원입니다."