카트id내려주기 / updateQuantityCart 구현 완료

src/main/java/com/clone/animan/controller/CartController.java

@@ -28,6 +28,11 @@ public void createCart(@PathVariable Long productId, @RequestBody CartRequestDto
         cartService.createCart(productId, requestDto);
     }
 
+    @PutMapping("/cart/update/{productId}")
+    public void updateCart(@PathVariable Long productId, @RequestBody CartRequestDto requestDto) {
+        cartService.updateQuantityCart(productId, requestDto);
+    }
+
     @DeleteMapping("/cart/{cartId}")
     public void deleteCart(@PathVariable Long cartId) {
         cartService.deleteCart(cartId);

src/main/java/com/clone/animan/dto/CartRequestDto.java

@@ -4,6 +4,7 @@
 
 @Getter
 public class CartRequestDto {
+    private Long cartId;
     private Long quantity;
     private Long productId;
     private String title;

src/main/java/com/clone/animan/service/CartService.java

@@ -48,6 +48,14 @@ public void updateCart(String username, Long productId, Long quantity) {
         cartRepository.save(cart);
     }
 
+    public void updateQuantityCart(Long productId, CartRequestDto requestDto) {
+        String username = requestDto.getUsername();
+        Long quantity = requestDto.getQuantity();
+        Cart cart = cartRepository.findByProductIdAndUsername(productId, username);
+        cart.update(quantity);
+        cartRepository.save(cart);
+    }
+
     public void deleteCart(Long cartId){
         cartRepository.deleteById(cartId);
     }