week 3

Readme.md

@@ -0,0 +1,32 @@
+## Java Implementation  
+
+#### 运行方式
+
+用./mvnw spring-boot:run运行
+h2 database在 localhost:8080/h2-console
+
+#### cURL测试
+
+用cURL测试/api/v1/product/create
+curl -X POST -H "Content-Type: application/json" --data '{"name":"product1","price":"1.0","stock":"5"}' http://localhost:8080/api/v1/product/create
+返回
+{"code":201,"name":"product1","message":"Product created"}
+
+再次用cURL测试/api/v1/product/create使用相同的name
+返回
+{"code":409,"message":"Product with the same name already exists"}
+
+用cURL测试/api/v1/product/{id}
+curl -X GET -H "Content-Type: application/json" http://localhost:8080/api/v1/product/product1
+返回
+{"product":{"price":1.0,"name":"product1","stock":5},"code":200,"message":"Product retrieved"}
+用cURL测试/api/v1/product/{id}使用不存在的name
+返回
+{"code":404,"message":"Product not found"}
+
+#### 代码结构
+- controller: 接受请求parameters然后调用service
+- service: 调用repository，处理业务逻辑。在必要时throw exception
+- repository: 继承JpaRepository，和database交互存储数据
+- product: Model class
+controller不直接调用repository,而是调用service负责业务逻辑。将来如要更改实现方式，只需更改service和repository，不用更改controller

pom.xml

@@ -34,11 +34,22 @@
 			<groupId>org.springframework.boot</groupId>
 			<artifactId>spring-boot-starter-data-jpa</artifactId>
 		</dependency>
+        <dependency>
+            <groupId>com.h2database</groupId>
+            <artifactId>h2</artifactId>
+            <scope>runtime</scope>
+        </dependency>
 		<dependency>
 			<groupId>org.springframework.boot</groupId>
 			<artifactId>spring-boot-starter-web</artifactId>
 		</dependency>
 
+        <dependency>
+            <groupId>org.json</groupId>
+            <artifactId>json</artifactId>
+            <version>20250517</version>
+        </dependency>
+
 		<dependency>
 			<groupId>org.springframework.boot</groupId>
 			<artifactId>spring-boot-starter-test</artifactId>

src/main/java/com/ljc42/demo/Controller/HelloController.java

@@ -1,13 +0,0 @@
-package com.ljc42.demo;
-
-import org.springframework.stereotype.Controller;
-import org.springframework.web.bind.annotation.GetMapping;
-
-@Controller
-public class HelloController {
-
-    @GetMapping("/")
-    public String hello() {
-        return "hello.json";
-    }
-}

src/main/java/com/ljc42/product/Controller/ProductController.java

@@ -0,0 +1,61 @@
+package com.ljc42.product.Controller;
+
+import com.ljc42.product.Exceptions.ProductExitsException;
+import com.ljc42.product.Exceptions.ProductNotFoundException;
+import com.ljc42.product.Model.Product;
+import com.ljc42.product.Service.ProductService;
+import org.json.JSONObject;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.*;
+
+import java.util.Map;
+import java.util.Objects;
+
+@RestController
+public class ProductController {
+
+    private final ProductService productService;
+
+    public ProductController(ProductService productService) {
+        this.productService = productService;
+    }
+
+    @GetMapping("/api/v1/product/{name}")
+    public ResponseEntity<Map<String,Object>> getProducts(@PathVariable String name) {
+        try {
+            Product product = this.productService.getProductByName(name);
+            JSONObject jsonProduct = new JSONObject();
+            jsonProduct.put("name", product.getName());
+            jsonProduct.put("price", product.getPrice());
+            jsonProduct.put("stock", product.getStock());
+            JSONObject responseBody = new JSONObject();
+            responseBody.put("code", 200);
+            responseBody.put("product", jsonProduct);
+            responseBody.put("message", "Product retrieved");
+            return new ResponseEntity<>(responseBody.toMap(), HttpStatus.OK);
+        } catch (ProductNotFoundException e) {
+            JSONObject responseBody = new JSONObject();
+            responseBody.put("code", 404);
+            responseBody.put("message", e.getMessage());
+            return new ResponseEntity<>(responseBody.toMap(), HttpStatus.NOT_FOUND);
+        }
+    }
+
+    @PostMapping("/api/v1/product/create")
+    public ResponseEntity<Map<String, Object>> createProducts(@RequestBody Product product) {
+        try {
+            this.productService.createProduct(product);
+            JSONObject responseBody = new JSONObject();
+            responseBody.put("code", 201);
+            responseBody.put("name", product.getName());
+            responseBody.put("message", "Product created");
+            return new ResponseEntity<>(responseBody.toMap(),HttpStatus.CREATED);
+        } catch (ProductExitsException e) {
+            JSONObject responseBody = new JSONObject();
+            responseBody.put("code", 409);
+            responseBody.put("message", e.getMessage());
+            return new ResponseEntity<>(responseBody.toMap(),HttpStatus.CONFLICT);
+        }
+    }
+}

src/main/java/com/ljc42/product/DemoApplication.java

@@ -1,10 +1,11 @@
-package com.ljc42.demo;
+package com.ljc42.product;
 
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
 import org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration;
 
-@SpringBootApplication(exclude = {DataSourceAutoConfiguration.class })
+//@SpringBootApplication(exclude = {DataSourceAutoConfiguration.class })
+@SpringBootApplication()
 public class DemoApplication {
 
 	public static void main(String[] args) {

src/main/java/com/ljc42/product/Exceptions/ProductExitsException.java

@@ -0,0 +1,7 @@
+package com.ljc42.product.Exceptions;
+
+public class ProductExitsException extends Exception{
+    public ProductExitsException(String message) {
+        super(message);
+    }
+}

src/main/java/com/ljc42/product/Exceptions/ProductNotFoundException.java

@@ -0,0 +1,7 @@
+package com.ljc42.product.Exceptions;
+
+public class ProductNotFoundException extends Exception{
+    public ProductNotFoundException(String message) {
+        super(message);
+    }
+}

src/main/java/com/ljc42/product/Model/Product.java

@@ -0,0 +1,48 @@
+package com.ljc42.product.Model;
+
+import jakarta.persistence.Entity;
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.Id;
+
+@Entity
+public class Product {
+    private @Id
+    @GeneratedValue Long id;
+    private String name;
+    private double price;
+    private int stock;
+
+    public Product() {
+
+    }
+
+    public Product(String name, double price, int stock) {
+        this.name = name;
+        this.price = price;
+        this.stock = stock;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public double getPrice() {
+        return price;
+    }
+
+    public void setPrice(double price) {
+        this.price = price;
+    }
+
+    public int getStock() {
+        return stock;
+    }
+
+    public void setStock(int stock) {
+        this.stock = stock;
+    }
+}

src/main/java/com/ljc42/product/Repository/ProductRepository.java

@@ -0,0 +1,9 @@
+package com.ljc42.product.Repository;
+
+import com.ljc42.product.Model.Product;
+import org.springframework.data.jpa.repository.JpaRepository;
+
+public interface ProductRepository extends JpaRepository<Product, Long> {
+    boolean existsByName(String name);
+    Product findByName(String name);
+}

src/main/java/com/ljc42/product/Service/ProductService.java

@@ -0,0 +1,31 @@
+package com.ljc42.product.Service;
+
+import com.ljc42.product.Exceptions.ProductNotFoundException;
+import com.ljc42.product.Model.Product;
+import com.ljc42.product.Repository.ProductRepository;
+import com.ljc42.product.Exceptions.ProductExitsException;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Service;
+
+@Service
+public class ProductService {
+
+    @Autowired
+    private ProductRepository productRepository;
+
+    public void createProduct(Product product) throws ProductExitsException{
+        if(productRepository.existsByName(product.getName())) {
+            throw new ProductExitsException("Product with the same name already exists");
+        } else {
+            this.productRepository.save(product);
+        }
+    }
+
+    public Product getProductByName(String name) throws ProductNotFoundException {
+        if(productRepository.existsByName(name)) {
+            return productRepository.findByName(name);
+        } else {
+            throw new ProductNotFoundException("Product not found");
+        }
+    }
+}

src/main/resources/application.properties

@@ -1 +1,7 @@
 spring.application.name=demo
+spring.h2.console.enabled=true
+spring.datasource.url=jdbc:h2:mem:app
+spring.datasource.driver-class-name=org.h2.Driver
+spring.datasource.username=sa
+spring.datasource.password=password
+spring.jpa.database-platform=org.hibernate.dialect.H2Dialect

src/test/java/com/ljc42/product/DemoApplicationTests.java

@@ -1,4 +1,4 @@
-package com.ljc42.demo;
+package com.ljc42.product;
 
 import org.junit.jupiter.api.Test;
 import org.springframework.boot.test.context.SpringBootTest;