[6주차] 장바구니 만들기

build.gradle.kts

@@ -16,12 +16,15 @@ repositories {
 }
 
 dependencies {
+    implementation ("org.springframework.boot:spring-boot-starter-data-jpa")
     implementation("org.springframework.boot:spring-boot-starter-web")
     implementation("org.springframework.boot:spring-boot-starter-validation")
 
     developmentOnly("org.springframework.boot:spring-boot-devtools")
 
     testImplementation("org.springframework.boot:spring-boot-starter-test")
+    testCompileOnly ("org.projectlombok:lombok")
+    testAnnotationProcessor ("org.projectlombok:lombok")
 }
 
 tasks.withType<Test> {

src/main/java/com/example/demo/application/CartService.java

@@ -0,0 +1,48 @@
+package com.example.demo.application;
+
+import com.example.demo.exception.CartNotFoundException;
+import com.example.demo.exception.ProductNotFoundException;
+import com.example.demo.model.Cart;
+import com.example.demo.model.LineItemId;
+import com.example.demo.model.ProductId;
+import com.example.demo.model.ProductOption;
+import com.example.demo.repository.CartRepository;
+import com.example.demo.repository.ProductRepository;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+
+@Service
+@Transactional
+public class CartService {
+
+    private final CartRepository cartRepository;
+    private final ProductRepository productRepository;
+
+    public CartService(CartRepository cartRepository, ProductRepository productRepository) {
+        this.cartRepository = cartRepository;
+        this.productRepository = productRepository;
+    }
+
+    public void addItemToCart(String userId, ProductId productId, ProductOption option, int quantity) {
+        Cart cart = getCart(userId);
+        if (!productRepository.existsById(productId)) {
+            throw new ProductNotFoundException(productId);
+        }
+        cart.addProduct(productId, option, quantity);
+    }
+
+    public void removeLineItem(String userId, LineItemId lineItemId) {
+        Cart cart = getCart(userId);
+        cart.removeLineItem(lineItemId);
+    }
+
+    public void clearCart(String userId) {
+        Cart cart = getCart(userId);
+        cart.clearItems();
+    }
+
+    public Cart getCart(String userId) {
+        return cartRepository.findByUserId(userId)
+                .orElseThrow(CartNotFoundException::new);
+    }
+}

src/main/java/com/example/demo/controllers/CartController.java

@@ -1,14 +1,65 @@
 package com.example.demo.controllers;
 
+import com.example.demo.application.CartService;
+import com.example.demo.controllers.dto.CartResponseDto;
+import com.example.demo.controllers.dto.LineItemResponseDto;
+import com.example.demo.model.Cart;
+import com.example.demo.util.AuthorizationUtils;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.DeleteMapping;
 import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RequestHeader;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RestController;
 
+import static com.example.demo.util.AuthorizationUtils.extractUserIdFromAuthorization;
+
 @RestController
 @RequestMapping("/cart")
 public class CartController {
+
+    private final CartService cartService;
+
+    public CartController(CartService cartService) {
+        this.cartService = cartService;
+    }
+
+
     @GetMapping
-    String detail() {
-        return "";
+    public ResponseEntity<CartResponseDto> getCart(
+            @RequestHeader(name = "Authorization", required = false)
+            String authorization) {
+
+        String userId = extractUserIdFromAuthorization(authorization);
+        Cart cart = cartService.getCart(userId);
+
+        CartResponseDto responseDto = new CartResponseDto(
+                cart.getTotalQuantity(),
+                cart.getLineItems().stream()
+                        .map(lineItem -> new LineItemResponseDto(
+                                        lineItem.getProductId().id(),
+                                        lineItem.getProductOption().color(),
+                                        lineItem.getProductOption().size(),
+                                        lineItem.getQuantity()
+                                )
+                        ).toList()
+        );
+
+        return new ResponseEntity<>(responseDto, HttpStatus.OK);
+    }
+
+
+    @DeleteMapping()
+    public ResponseEntity<Void> deleteCart(
+            @RequestHeader(name = "Authorization", required = false)
+            String authorization) {
+
+        String userId = extractUserIdFromAuthorization(authorization);
+
+        cartService.clearCart(userId);
+        return new ResponseEntity<>(HttpStatus.NO_CONTENT);
     }
+
+
 }

src/main/java/com/example/demo/controllers/LineItemController.java

@@ -1,17 +1,62 @@
 package com.example.demo.controllers;
 
+import com.example.demo.application.CartService;
+import com.example.demo.controllers.dto.LineItemRequestDto;
+import com.example.demo.exception.UnauthorizedException;
+import com.example.demo.model.Cart;
+import com.example.demo.model.LineItemId;
+import com.example.demo.model.ProductId;
+import com.example.demo.model.ProductOption;
+import jakarta.validation.Valid;
 import org.springframework.http.HttpStatus;
+import org.springframework.web.bind.annotation.DeleteMapping;
+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.RequestHeader;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.ResponseStatus;
 import org.springframework.web.bind.annotation.RestController;
 
+import static com.example.demo.util.AuthorizationUtils.extractUserIdFromAuthorization;
+
+
 @RestController
 @RequestMapping("/cart/line-items")
 public class LineItemController {
+
+    public LineItemController(CartService cartService) {
+        this.cartService = cartService;
+    }
+
+    private final CartService cartService;
+
     @PostMapping
     @ResponseStatus(HttpStatus.CREATED)
-    void create() {
-        //
+    public void create(
+            @Valid @RequestBody LineItemRequestDto requestDto,
+            @RequestHeader("Authorization") String authorization) {
+
+        String userId = extractUserIdFromAuthorization(authorization);
+
+        cartService.addItemToCart(
+                userId,
+                new ProductId(requestDto.productId()),
+                new ProductOption(requestDto.color(), requestDto.size()),
+                requestDto.quantity());
+
+    }
+
+    @DeleteMapping("/{lineItemId}")
+    @ResponseStatus(HttpStatus.NO_CONTENT)
+    public void deleteLineItem(
+            @PathVariable String lineItemId,
+            @RequestHeader("Authorization") String authorization) {
+
+        String userId = extractUserIdFromAuthorization(authorization);
+
+        cartService.removeLineItem(
+                userId,
+                new LineItemId(lineItemId));
     }
 }

src/main/java/com/example/demo/controllers/dto/CartResponseDto.java

@@ -0,0 +1,9 @@
+package com.example.demo.controllers.dto;
+
+import java.util.List;
+
+public record CartResponseDto(
+        int totalQuantity,
+        List<LineItemResponseDto> lineItems
+) {
+}

src/main/java/com/example/demo/controllers/dto/LineItemRequestDto.java

@@ -0,0 +1,22 @@
+package com.example.demo.controllers.dto;
+
+import jakarta.validation.constraints.Max;
+import jakarta.validation.constraints.Min;
+import jakarta.validation.constraints.NotBlank;
+
+public record LineItemRequestDto(
+
+        @NotBlank(message = "상품 ID는 필수입니다.")
+        String productId,
+
+        @NotBlank(message = "색상은 필수입니다.")
+        String color,
+
+        @NotBlank(message = "사이즈는 필수입니다.")
+        String size,
+
+        @Min(value = 1, message = "최소 수량은 1개입니다.")
+        @Max(value = 20, message = "최대 수량은 20개입니다.")
+        int quantity
+) {
+}

src/main/java/com/example/demo/controllers/dto/LineItemResponseDto.java

@@ -0,0 +1,10 @@
+package com.example.demo.controllers.dto;
+
+public record LineItemResponseDto(
+        String productId,
+        String color,
+        String size,
+        int quantity
+) {
+
+}

src/main/java/com/example/demo/exception/CartNotFoundException.java

@@ -0,0 +1,7 @@
+package com.example.demo.exception;
+
+public class CartNotFoundException extends RuntimeException {
+    public CartNotFoundException() {
+        super("장바구니를 찾을 수 없습니다.");
+    }
+}

src/main/java/com/example/demo/exception/CartQuantityLimitException.java

@@ -0,0 +1,7 @@
+package com.example.demo.exception;
+
+public class CartQuantityLimitException extends RuntimeException {
+    public CartQuantityLimitException() {
+        super("장바구니에 담을 수 있는 수량을 초과했습니다.");
+    }
+}

src/main/java/com/example/demo/exception/ErrorResponseDto.java

@@ -0,0 +1,8 @@
+package com.example.demo.exception;
+
+
+public record ErrorResponseDto(
+        String code,
+        String message
+) {
+}

src/main/java/com/example/demo/exception/GlobalExceptionHandler.java

@@ -0,0 +1,40 @@
+package com.example.demo.exception;
+
+
+import org.springframework.http.HttpStatus;
+import org.springframework.http.MediaType;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.ExceptionHandler;
+import org.springframework.web.bind.annotation.RestControllerAdvice;
+
+@RestControllerAdvice
+public class GlobalExceptionHandler {
+
+    @ExceptionHandler(CartNotFoundException.class)
+    public ResponseEntity<ErrorResponseDto> handleCartNotFound(CartNotFoundException e) {
+        ErrorResponseDto responseDto = new ErrorResponseDto("CART_NOT_FOUND", e.getMessage());
+        return new ResponseEntity<>(responseDto, HttpStatus.NOT_FOUND);
+    }
+
+    @ExceptionHandler(ProductNotFoundException.class)
+    public ResponseEntity<ErrorResponseDto> handleProductNotFound(ProductNotFoundException e) {
+        ErrorResponseDto responseDto = new ErrorResponseDto("PRODUCT_NOT_FOUND", e.getMessage());
+        return new ResponseEntity<>(responseDto, HttpStatus.NOT_FOUND);
+    }
+
+    @ExceptionHandler(CartQuantityLimitException.class)
+    public ResponseEntity<ErrorResponseDto> handleCartQuantityLimit(CartQuantityLimitException e) {
+        ErrorResponseDto responseDto = new ErrorResponseDto("CART_QUANTITY_LIMIT", e.getMessage());
+        return ResponseEntity
+                .status(HttpStatus.BAD_REQUEST)
+                .contentType(MediaType.APPLICATION_JSON)
+                .body(responseDto);
+    }
+
+    @ExceptionHandler(UnauthorizedException.class)
+    public ResponseEntity<ErrorResponseDto> handleUnauthorized(UnauthorizedException e) {
+        ErrorResponseDto responseDto = new ErrorResponseDto("UNAUTHORIZED", e.getMessage());
+        return new ResponseEntity<>(responseDto, HttpStatus.UNAUTHORIZED);
+    }
+
+}

src/main/java/com/example/demo/exception/ProductNotFoundException.java

@@ -0,0 +1,9 @@
+package com.example.demo.exception;
+
+import com.example.demo.model.ProductId;
+
+public class ProductNotFoundException extends RuntimeException {
+    public ProductNotFoundException(ProductId productId) {
+        super("상품을 찾을 수 없습니다. ID: " + productId.id());
+    }
+}

src/main/java/com/example/demo/exception/UnauthorizedException.java

@@ -0,0 +1,7 @@
+package com.example.demo.exception;
+
+public class UnauthorizedException extends RuntimeException {
+    public UnauthorizedException() {
+        super("인증이 필요합니다.");
+    }
+}