woowacourse-study · kwonyj1022 · Aug 1, 2023
diff --git a/레벨3/3주차/엔초-ServletUriComponentsBuilder.md b/레벨3/3주차/엔초-ServletUriComponentsBuilder.md
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+# ServletUriComponentsBuilder
+
+# ServletUriComponentsBuilder란?
+
+- Spring Framework에서 제공하는 유틸리티 클래스
+- URI(Uniform Resource Identifier)를 생성하고 조작하는 데 사용
+    - URI: 인터넷에서 리소스를 고유하게 식별하는 표준화된 문자열
+- 주로 웹 애플리케이션에서 동적인 URI를 생성해야 할 때 사용
+    - 컨트롤러에서 클라이언트의 요청을 처리한 후, 해당 요청과 관련된 URI를 생성하는 데 사용
+    - 즉, 현재 요청에 대한 정보를 바탕으로 URI를 생성하고 수정할 수 있음
+    - ex) 특정 리소스에 대한 URI를 생성하거나, 쿼리 매개변수를 추가하여 동적인 URI를 생성하는 경우
+
+## ServletUriComponentsBuilder 사용법
+
+### 자주 사용하는 메서드
+
+- `**fromCurrentContextPath()`**
+    - 현재 **컨텍스트 경로**를 기반으로 `ServletUriComponentsBuilder` 생성
+- `**fromCurrentRequest()**`
+    - 현재 **요청**을 기반으로 `ServletUriComponentsBuilder` 객체 생성
+- `**path(String path)**`
+    - 만들어진 uri에 경로 추가
+    - 경로 변수를 사용하여 동적인 경로 생성 가능
+- `**queryParam(String name, Object... values)**`
+    - 만들어진 uri에 쿼리 매개변수 추가
+
+### 사용법
+
+1. `fromCurrentRequest()` 또는 `fromCurrentContextPath()` 메서드를 사용하여 `ServletUriComponentsBuilder` 객체를 생성
+    - HttpServletRequest를 파라미터로 받아 생성하기도 함
+2. 필요한 경우, `path()` 메서드를 사용하여 경로 추가
+3. 필요한 경우, `queryParam()` 메서드를 사용하여 Query Parameter 추가
+4. build() 메서드를 호출하여 생성된 URI를 완성합니다.
+
+## 주요 메서드 활용 예시
+
+### `**fromCurrentContextPath()**`
+
+```java
+@RestController
+@RequestMapping("/members")
+@RequiredArgsConstructor
+public class MemberController {
+
+    private final MemberService memberService;
+
+    @PostMapping
+    public ResponseEntity<Void> create(@RequestBody MemberRequest request) {
+        memberService.create(request);
+
+        URI uri = ServletUriComponentsBuilder.fromCurrentContextPath()
+                                             .build()
+                                             .toUri();
+
+        return ResponseEntity.created(uri).build();
+    }
+}
+```
+
+- http://localhost:8080/members 로 POST 요청을 했다면
+uri = “http://localhost:8080”
+
+    ![fromCurrentContextPath](https://rapid-browser-8fb.notion.site/image/https%3A%2F%2Fs3-us-west-2.amazonaws.com%2Fsecure.notion-static.com%2Fb0f106db-ff02-4dfa-9aed-07de3a70e952%2F%25E1%2584%2589%25E1%2585%25B3%25E1%2584%258F%25E1%2585%25B3%25E1%2584%2585%25E1%2585%25B5%25E1%2586%25AB%25E1%2584%2589%25E1%2585%25A3%25E1%2586%25BA_2023-07-31_%25E1%2584%258B%25E1%2585%25A9%25E1%2584%2592%25E1%2585%25AE_12.14.42.png?table=block&id=73970f1b-7592-4789-9d68-cfe5e243e73e&spaceId=46a9d753-8b1d-4083-bd7d-4b5f6daf3c1f&width=2000&userId=&cache=v2)
+
+
+### `fromCurrentRequest()`
+
+```java
+@RestController
+@RequestMapping("/members")
+@RequiredArgsConstructor
+public class MemberController {
+
+    private final MemberService memberService;
+
+    @PostMapping
+    public ResponseEntity<Void> create(@RequestBody MemberRequest request) {
+        memberService.create(request);
+
+        URI uri = ServletUriComponentsBuilder.fromCurrentRequest()
+                                             .build()
+                                             .toUri();
+
+        return ResponseEntity.created(uri).build();
+    }
+}
+```
+
+- http://localhost:8080/members 로 POST 요청을 했다면
+uri = “http://localhost:8080/members”
+
+    ![fromCurrentRequest](https://rapid-browser-8fb.notion.site/image/https%3A%2F%2Fs3-us-west-2.amazonaws.com%2Fsecure.notion-static.com%2F12b1b872-d0d8-4e3f-89ef-bf8e00e61c08%2F%25E1%2584%2589%25E1%2585%25B3%25E1%2584%258F%25E1%2585%25B3%25E1%2584%2585%25E1%2585%25B5%25E1%2586%25AB%25E1%2584%2589%25E1%2585%25A3%25E1%2586%25BA_2023-07-31_%25E1%2584%258B%25E1%2585%25A9%25E1%2584%2592%25E1%2585%25AE_12.15.44.png?table=block&id=9f33552f-8fa9-4dc0-9062-4a7b6e0ae13d&spaceId=46a9d753-8b1d-4083-bd7d-4b5f6daf3c1f&width=2000&userId=&cache=v2)
+
+
+### `path(String path)`
+
+```java
+@RestController
+@RequestMapping("/members")
+@RequiredArgsConstructor
+public class MemberController {
+
+    private final MemberService memberService;
+
+    @PostMapping
+    public ResponseEntity<Void> create(@RequestBody final MemberRequest request) {
+        final Long memberId = memberService.create(request);
+
+//        URI uri = ServletUriComponentsBuilder.fromCurrentRequest()
+//                                             .path("/" + memberId)
+//                                             .build()
+//                                             .toUri();
+
+        URI uri = ServletUriComponentsBuilder.fromCurrentRequest()
+                                              .path("/{memberId}")
+                                              .buildAndExpand(memberId)
+                                              .toUri();
+
+        return ResponseEntity.created(uri).build();
+    }
+}
+```
+
+- http://localhost:8080/members 로 POST 요청을 했다면
+uri = “http://localhost:8080/members/{memberId}”
+
+    ![path](https://rapid-browser-8fb.notion.site/image/https%3A%2F%2Fs3-us-west-2.amazonaws.com%2Fsecure.notion-static.com%2Fcdc155c9-d0f2-4c6a-92f3-0f784efcce70%2F%25E1%2584%2589%25E1%2585%25B3%25E1%2584%258F%25E1%2585%25B3%25E1%2584%2585%25E1%2585%25B5%25E1%2586%25AB%25E1%2584%2589%25E1%2585%25A3%25E1%2586%25BA_2023-07-31_%25E1%2584%258B%25E1%2585%25A9%25E1%2584%2592%25E1%2585%25AE_1.09.45.png?table=block&id=94fcce8a-0844-40b4-8f95-494f1d2a447d&spaceId=46a9d753-8b1d-4083-bd7d-4b5f6daf3c1f&width=2000&userId=&cache=v2)
+
+
+### `queryParam(String name, Object... values)`
+
+```java
+@RestController
+@RequestMapping("/products")
+@RequiredArgsConstructor
+public class ProductController {
+
+    private final ProductService productService;
+
+    @PostMapping
+    public ResponseEntity<Void> create() {
+        productService.create(request);
+
+        URI uri = ServletUriComponentsBuilder
+                            .fromCurrentRequest()
+                            .queryParam("category", "electronics", "fashion")
+														.queryParam("sort", "time")
+                            .build()
+                            .toUri();
+
+        return ResponseEntity.created(uri).build();
+    }
+}
+```
+
+```java
+@RestController
+@RequestMapping("/products")
+@RequiredArgsConstructor
+public class ProductController {
+
+    private final ProductService productService;
+
+    @PostMapping
+    public ResponseEntity<Void> create() {
+        productService.create(request);
+
+        String[] categories = {"electronics", "fashion"};
+        URI uri = ServletUriComponentsBuilder.fromCurrentRequest()
+                                             .queryParam("category", categories)
+                                             .build()
+                                             .toUri();
+
+        return ResponseEntity.created(uri).build();
+    }
+}
+```
+
+- http://localhost:8080/products 로 요청했다면
+uri = “http://localhost:8080/products/category=electronics&category=fashion”
+
+    ![queryParam](https://rapid-browser-8fb.notion.site/image/https%3A%2F%2Fs3-us-west-2.amazonaws.com%2Fsecure.notion-static.com%2F68e95b32-728d-43d3-bc67-2face7be4caa%2FUntitled.png?table=block&id=fa595dde-6f6f-467b-8f64-2b90454afbe2&spaceId=46a9d753-8b1d-4083-bd7d-4b5f6daf3c1f&width=2000&userId=&cache=v2)