feat: 增加获取单个商品的功能

src/main/java/com/seecoder/BlueWhale/controller/ProductController.java

@@ -29,4 +29,9 @@ public class ProductController {
     public ResultVO<List<ProductVO>> getAllProducts(@RequestParam("storeId") Integer storeId){
         return ResultVO.buildSuccess(productService.getAllProducts(storeId));
     }
+
+    @GetMapping("/{id}")
+    public ResultVO<ProductVO> getProduct(@PathVariable(value = "id") Integer id){
+        return ResultVO.buildSuccess(productService.getProduct(id));
+    }
 }

src/main/java/com/seecoder/BlueWhale/service/ProductService.java

@@ -8,4 +8,5 @@ public interface ProductService {
     Boolean create(ProductVO productVO);
     Boolean addStock(Integer id, Integer number);
     List<ProductVO> getAllProducts(Integer storeId);
+    ProductVO getProduct(Integer id);
 }

src/main/java/com/seecoder/BlueWhale/serviceImpl/ProductServiceImpl.java

@@ -56,4 +56,13 @@ public class ProductServiceImpl implements ProductService {
         }
         return productRepository.findAllByStoreId(storeId).stream().map(Product::toVO).collect(Collectors.toList());
     }
+
+    @Override
+    public ProductVO getProduct(Integer id) {
+        Product product=productRepository.findById(id).orElse(null);
+        if(product==null){
+            throw BlueWhaleException.productNotExists();
+        }
+        return product.toVO();
+    }
 }