Feature/1

src/main/java/com/e_co/e_commerce/config/LoadDatabase.java

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+package com.e_co.e_commerce.config;
+
+import com.e_co.e_commerce.product.Product;
+import com.e_co.e_commerce.product.ProductService;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.boot.CommandLineRunner;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+import java.util.Random;
+
+@Configuration
+class LoadDatabase {
+
+    private static final Logger log = LoggerFactory.getLogger(LoadDatabase.class);
+
+    @Bean
+    CommandLineRunner initDatabase(ProductService productService) {
+
+        return args -> {
+            // 프로덕트 등록
+            for (int i = 0; i < 25; i++) {
+                Random random = new Random();
+                log.info("Preloading {}", productService.save(new Product("TestProduct" + i, random.nextInt(10) * 1000 + 10000, "", random.nextInt(10), 1)));
+            }
+        };
+    }
+}

src/main/java/com/e_co/e_commerce/product/Product.java

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+package com.e_co.e_commerce.product;
+
+import jakarta.persistence.Entity;
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.GenerationType;
+import jakarta.persistence.Id;
+
+import java.util.Objects;
+
+@Entity
+public class Product {
+    @Id @GeneratedValue(strategy = GenerationType.AUTO)
+    private Long id;
+
+    private String name;
+    private int price;
+    private String description;
+    private int stock;
+    private int sellerId;
+
+    public Product() {
+
+    }
+
+    public Product(String name, int price, String description, int stock, int sellerId) {
+        this.name = name;
+        this.price = price;
+        this.description = description;
+        this.stock = stock;
+        this.sellerId = sellerId;
+    }
+
+    public Long getId() {
+        return id;
+    }
+
+    public void setId(Long id) {
+        this.id = id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public int getPrice() {
+        return price;
+    }
+
+    public void setPrice(int price) {
+        this.price = price;
+    }
+
+    public String getDescription() {
+        return description;
+    }
+
+    public void setDescription(String description) {
+        this.description = description;
+    }
+
+    public int getStock() {
+        return stock;
+    }
+
+    public void setStock(int stock) {
+        this.stock = stock;
+    }
+
+    public int getSellerId() {
+        return sellerId;
+    }
+
+    public void setSellerId(int sellerId) {
+        this.sellerId = sellerId;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (!(o instanceof Product product)) return false;
+        return price == product.price && stock == product.stock && sellerId == product.sellerId && Objects.equals(id, product.id) && Objects.equals(name, product.name) && Objects.equals(description, product.description);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(id, name, price, description, stock, sellerId);
+    }
+
+    @Override
+    public String toString() {
+        return "Product{" +
+                "id=" + id +
+                ", name='" + name + '\'' +
+                ", price=" + price +
+                ", description='" + description + '\'' +
+                ", stock=" + stock +
+                ", sellerId=" + sellerId +
+                '}';
+    }
+}

src/main/java/com/e_co/e_commerce/product/ProductController.java

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+package com.e_co.e_commerce.product;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.data.domain.Page;
+import org.springframework.data.domain.Pageable;
+import org.springframework.data.web.PageableDefault;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RequestParam;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+public class ProductController {
+    private ProductService productService;
+
+    @Autowired
+    public void setProductService(ProductService productService) {
+        this.productService = productService;
+    }
+
+    @GetMapping("/product")
+    public ResponseEntity<Product> getProduct(@RequestParam("id") long id) {
+        Product product = productService.getProduct(id);
+        return new ResponseEntity<>(product, HttpStatus.OK);
+    }
+
+    @GetMapping("/products")
+    public ResponseEntity<Page<Product>> getProducts(@RequestParam(value = "name", required = false) String name,
+                                                     @RequestParam(value = "description", required = false) String description,
+                                                     @RequestParam(value = "isOnlyExist", defaultValue = "true", required = false) boolean isOnlyExist,
+                                                     @PageableDefault Pageable pageable
+    ) {
+        Page<Product> products = productService.getProducts(name, description, isOnlyExist, pageable);
+
+        return new ResponseEntity<>(products, HttpStatus.OK);
+    }
+}

src/main/java/com/e_co/e_commerce/product/ProductRepository.java

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+package com.e_co.e_commerce.product;
+
+import org.springframework.data.domain.Page;
+import org.springframework.data.domain.Pageable;
+import org.springframework.data.repository.CrudRepository;
+
+public interface ProductRepository extends CrudRepository<Product, Long> {
+    // 페이지네이션, ((이름 or 내용) and 품절여부) 조건이 기본적으로 적용된 쿼리
+    // 정렬도 사용 가능
+    Page<Product> findAllByNameOrDescriptionOrStockGreaterThanEqual(String name, String description, int stock, Pageable pageable);
+}

src/main/java/com/e_co/e_commerce/product/ProductService.java

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+package com.e_co.e_commerce.product;
+
+import org.springframework.data.domain.Page;
+import org.springframework.data.domain.Pageable;
+
+public interface ProductService {
+    long getCount();
+
+    Product save(Product product);
+
+    Product getProduct(long id);
+
+    /**
+     * 페이지네이션, 필터, 정렬이 적용된 여러 상품 가져오기
+     */
+    Page<Product> getProducts(String name, String description, boolean isOnlyExist, Pageable pageable);
+}

src/main/java/com/e_co/e_commerce/product/ProductServiceImpl.java

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+package com.e_co.e_commerce.product;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.data.domain.Page;
+import org.springframework.data.domain.Pageable;
+import org.springframework.stereotype.Service;
+
+@Service
+public class ProductServiceImpl implements ProductService {
+    private ProductRepository productRepository;
+
+    @Autowired
+    public void setProductRepository(ProductRepository productRepository) {
+        this.productRepository = productRepository;
+    }
+
+    @Override
+    public long getCount() {
+        return productRepository.count();
+    }
+
+    @Override
+    public Product save(Product product) {
+        return productRepository.save(product);
+    }
+
+    @Override
+    public Product getProduct(long id) {
+        return productRepository.findById(id).orElseThrow();
+    }
+
+    @Override
+    public Page<Product> getProducts(String name, String description, boolean isOnlyExist, Pageable pageable) {
+        return productRepository.findAllByNameOrDescriptionOrStockGreaterThanEqual(name, description, isOnlyExist ? 1 : 0, pageable);
+    }
+}

src/test/java/com/e_co/e_commerce/product/ProductRepositoryTest.java

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+package com.e_co.e_commerce.product;
+
+import net.bytebuddy.utility.RandomString;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.data.domain.Page;
+import org.springframework.data.domain.PageRequest;
+import org.springframework.data.domain.Pageable;
+import org.springframework.data.domain.Sort;
+
+import java.util.ArrayList;
+import java.util.Comparator;
+import java.util.List;
+import java.util.Random;
+
+@SpringBootTest
+public class ProductRepositoryTest {
+    @Autowired
+    ProductRepository productRepository;
+    List<Product> products;
+
+    @BeforeEach
+    public void setUp() {
+        productRepository.deleteAll();
+
+        products = new ArrayList<>();
+        for (int i = 0; i < 25; i++) {
+            Random random = new Random();
+            products.add(new Product("TestProduct" + i, random.nextInt(10) * 1000 + 10000, RandomString.make(), random.nextInt(10), 1));
+        }
+    }
+
+    @Test
+    public void save() {
+        assertEquals(0, productRepository.count());
+
+        ArrayList<Product> savedProducts = new ArrayList<>();
+        for (Product product : products) {
+            savedProducts.add(productRepository.save(product));
+        }
+
+        assertEquals(products.size(), productRepository.count());
+
+        for (Product product : savedProducts) {
+            assertEquals(product, productRepository.findById(product.getId()).orElseThrow(() -> new RuntimeException()));
+        }
+    }
+
+
+    // 페이지네이션, 조건, 정렬이 적용된 쿼리 테스트
+    @Test
+    public void findAllByNameOrDescription() {
+        String filterName = "";
+        String filterDescription = "";
+        boolean filterOnlyExist = false;
+
+        // 테스트 데이터를 자바 코드를 통해 쿼리에 맞춰 조건과 정렬 적용
+        List<Product> findProducts = products.stream().filter(product -> {
+            return (product.getName().contains(filterName) || product.getDescription().contains(filterDescription)) && product.getStock() >= (filterOnlyExist ? 1 : 0);
+        }).sorted(Comparator.comparingLong((Product p) -> p.getPrice()).reversed().thenComparing(p -> p.getId())).toList();
+
+        int pageSize = 10;
+        int pageTotal = (int) (Math.ceil((double) findProducts.size() / pageSize));
+
+        for (int i = 0; i < pageTotal; i++) {
+            Pageable pageable = PageRequest.of(i, pageSize, Sort.by("price").descending());
+            Page<Product> pages = productRepository.findAllByNameOrDescriptionOrStockGreaterThanEqual(filterName, filterDescription, filterOnlyExist ? 1 : 0, pageable);
+
+            assertEquals(pageTotal, pages.getTotalPages());
+            assertEquals(pageSize, pages.getSize());
+            assertEquals(findProducts.size(), pages.getTotalElements());
+
+            // 현재 쿼리가 ID 순서를 보장하지 못해 쿼리로 나온 페이지와 자바 코드로 나온 페이지 요소가 달라
+            // 요소별 테스트가 힘듬
+            // 이미 검증된 Spring Data JPA Repository 테스트에 가까워서 급하진 않기때문에
+            // 우선 요소 테스트 코드 작성은 패스
+
+            //List<Product> pagedProducts = findProducts.subList(i * pageSize, (i < pageTotal - 1) ? (i + 1) * pageSize : findProducts.size());
+            //// DB Query가 Id 순서를 보장하지 않아 자바 코드로 임시로 정렬
+            //List<Product> realPagedProducts = pages.getContent().stream().sorted(Comparator.comparingLong((Product p) -> p.getPrice()).reversed().thenComparing(p -> p.getId())).toList();
+            //for (int j = 0; j < pagedProducts.size(); j++) {
+            //    assertEquals(pagedProducts.get(j), realPagedProducts.get(j));
+            //}
+        }
+    }
+}