[Refactor] feat: 전역 예외 처리 추가 및 URL 단축 로직 분리

src/main/java/community/whatever/onembackendjava/common/exception/GlobalExceptionHandler.java

@@ -0,0 +1,17 @@
+package community.whatever.onembackendjava.common.exception;
+
+import community.whatever.onembackendjava.common.exception.notfound.NotFoundShortenUrlException;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.ExceptionHandler;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+public class GlobalExceptionHandler {
+
+    @ExceptionHandler(NotFoundShortenUrlException.class)
+    public ResponseEntity<String> handleNotFoundShortenUrlException(NotFoundShortenUrlException ex) {
+        return new ResponseEntity<>("단축 URL을 찾지 못했습니다.", HttpStatus.NOT_FOUND);
+    }
+
+}

src/main/java/community/whatever/onembackendjava/common/exception/notfound/NotFoundShortenUrlException.java

@@ -0,0 +1,6 @@
+package community.whatever.onembackendjava.common.exception.notfound;
+
+
+public class NotFoundShortenUrlException extends RuntimeException {
+
+}

src/main/java/community/whatever/onembackendjava/component/UrlShortener.java

@@ -0,0 +1,14 @@
+package community.whatever.onembackendjava.component;
+
+import java.util.Random;
+import org.springframework.stereotype.Component;
+
+public class UrlShortener {
+
+    private static final Random RANDOM = new Random();
+
+    public String shorten() {
+        return String.valueOf(RANDOM.nextInt(10000));
+    }
+
+}

src/main/java/community/whatever/onembackendjava/controller/UrlShortenController.java

@@ -0,0 +1,34 @@
+package community.whatever.onembackendjava.controller;
+
+import community.whatever.onembackendjava.controller.response.GetOriginUrlResponse;
+import community.whatever.onembackendjava.controller.request.ShortenUrlRequest;
+import community.whatever.onembackendjava.controller.response.ShortenUrlResponse;
+import community.whatever.onembackendjava.service.UrlShortenService;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+public class UrlShortenController {
+
+    private final UrlShortenService urlShortenService;
+
+    public UrlShortenController(UrlShortenService urlShortenService) {
+        this.urlShortenService = urlShortenService;
+    }
+
+    @PostMapping("/shorten-url")
+    public ShortenUrlResponse createShortenUrl(@RequestBody ShortenUrlRequest request) {
+        String shortenUrl = urlShortenService.createShortenUrl(request.originUrl());
+        return new ShortenUrlResponse(shortenUrl);
+    }
+
+    @GetMapping("/shorten-url/{shortenUrlKey}")
+    public GetOriginUrlResponse getOriginUrlByShortenUrlKey(@PathVariable String shortenUrlKey) {
+        String originUrl = urlShortenService.getOriginUrlByShortenUrlKey(shortenUrlKey);
+        return new GetOriginUrlResponse(originUrl);
+    }
+
+}

src/main/java/community/whatever/onembackendjava/controller/request/ShortenUrlRequest.java

@@ -0,0 +1,7 @@
+package community.whatever.onembackendjava.controller.request;
+
+public record ShortenUrlRequest(
+    String originUrl
+) {
+
+}

src/main/java/community/whatever/onembackendjava/controller/response/GetOriginUrlResponse.java

@@ -0,0 +1,6 @@
+package community.whatever.onembackendjava.controller.response;
+
+public record GetOriginUrlResponse (
+    String originUrl
+){
+}

src/main/java/community/whatever/onembackendjava/controller/response/ShortenUrlResponse.java

@@ -0,0 +1,6 @@
+package community.whatever.onembackendjava.controller.response;
+
+public record ShortenUrlResponse (
+    String shortenUrlKey
+){
+}

src/main/java/community/whatever/onembackendjava/repository/UrlShortenRepository.java

@@ -0,0 +1,20 @@
+package community.whatever.onembackendjava.repository;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Optional;
+import org.springframework.stereotype.Repository;
+
+@Repository
+public class UrlShortenRepository {
+
+    private final Map<String, String> shortenUrls = new HashMap<>();
+
+    public Optional<String> findByShortenUrlKey(String shortenUrlKey) {
+        return Optional.ofNullable(shortenUrls.get(shortenUrlKey));
+    }
+
+    public void save(String shortenUrlKey, String originUrl) {
+        shortenUrls.put(shortenUrlKey, originUrl);
+    }
+}

src/main/java/community/whatever/onembackendjava/service/UrlShortenService.java

@@ -0,0 +1,30 @@
+package community.whatever.onembackendjava.service;
+
+import community.whatever.onembackendjava.common.exception.notfound.NotFoundShortenUrlException;
+import community.whatever.onembackendjava.component.UrlShortener;
+import community.whatever.onembackendjava.repository.UrlShortenRepository;
+import org.springframework.stereotype.Service;
+
+@Service
+public class UrlShortenService {
+
+    private final UrlShortenRepository urlShortenRepository;
+    private final UrlShortener urlShortener;
+
+    public UrlShortenService(UrlShortenRepository urlShortenRepository) {
+        this.urlShortenRepository = urlShortenRepository;
+        this.urlShortener = new UrlShortener();
+    }
+
+    public String createShortenUrl(String originUrl) {
+        String shortenUrlKey = urlShortener.shorten();
+        urlShortenRepository.save(shortenUrlKey, originUrl);
+        return shortenUrlKey;
+    }
+
+    public String getOriginUrlByShortenUrlKey(String shortenUrlKey) {
+        return urlShortenRepository.findByShortenUrlKey(shortenUrlKey)
+            .orElseThrow(NotFoundShortenUrlException::new);
+    }
+
+}

src/test/java/community/whatever/onembackendjava/application/UrlShortenServiceTest.java

@@ -3,8 +3,9 @@
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.junit.jupiter.api.Assertions.*;
 
+import community.whatever.onembackendjava.common.exception.notfound.NotFoundShortenUrlException;
+import community.whatever.onembackendjava.service.UrlShortenService;
 import java.util.NoSuchElementException;
-import org.junit.jupiter.api.DisplayName;
 import org.junit.jupiter.api.Test;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.test.context.SpringBootTest;
@@ -19,17 +20,17 @@ class UrlShortenServiceTest {
     void shorten_url을_생성하고_조회한다() {
         String expectedOriginUrl = "https://www.google.com";
         String key = urlShortenService.createShortenUrl(expectedOriginUrl);
-        String originUrl = urlShortenService.getOriginUrlByKey(key);
+        String originUrl = urlShortenService.getOriginUrlByShortenUrlKey(key);
 
         assertThat(originUrl).isEqualTo(expectedOriginUrl);
     }
 
     @Test
-    void 존재하지_않는_key로_조회하면_예외가_발생한다() {
+    void 존재하지_않는_shorten_url_key로_조회하면_예외가_발생한다() {
         String nonExistingKey = "nonExistingKey";
 
-        assertThrows(NoSuchElementException.class, () -> {
-            urlShortenService.getOriginUrlByKey(nonExistingKey);
+        assertThrows(NotFoundShortenUrlException.class, () -> {
+            urlShortenService.getOriginUrlByShortenUrlKey(nonExistingKey);
         });
     }