Tuturial 5: Toegang tot database vanuit de applicatie

We hebben de database structuur gegeven en gevuld met testdata. We zijn nu klaar om deze data te gaan gebruiken in de applicatie. In deze tutorial kijken we hoe we data uit de H2 database kunnen opvragen en deze kunnen gebruiken in onze API.

https://tweakers.net/advertorials/onlinejavaacademy2/tutorial5/

Author: vincentKool

src/main/java/tutorial/api/controllers/ProductController.java

@@ -1,33 +1,27 @@
 package tutorial.api.controllers;
 
-import org.springframework.web.bind.annotation.PathVariable;
-import org.springframework.web.bind.annotation.RequestMapping;
-import org.springframework.web.bind.annotation.RequestMethod;
-import org.springframework.web.bind.annotation.RestController;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.web.bind.annotation.*;
 import tutorial.persistence.models.Product;
+import tutorial.persistence.repositories.ProductRepository;
 
 import java.math.BigDecimal;
-import java.util.ArrayList;
 import java.util.List;
 
 @RestController
 public class ProductController extends ApiController {
 
+    @Autowired
+    ProductRepository productRepository;
+
     @RequestMapping(value="/products", method=RequestMethod.GET)
     public List<Product> showAll() {
-        List<Product> products = new ArrayList<>();
-
-        products.add(new Product(1, "Macbook Air", new BigDecimal("999.95")));
-        products.add(new Product(2, "Microsoft Surface 3", new BigDecimal("449")));
-        products.add(new Product(3, "Chromebook Pixel C", new BigDecimal("595.50"))
-        );
-
-        return products;
+        return (List<Product>) productRepository.findAll();
     }
 
     @RequestMapping(value="/products/{productId}", method=RequestMethod.GET)
     public Product show(@PathVariable("productId") long productId) {
-        return new Product(productId, "Macbook Air", new BigDecimal("999.95"));
+        return productRepository.findOne(productId);
     }
 
-}
+}

src/main/java/tutorial/api/controllers/ProductListController.java

@@ -1,49 +1,29 @@
 package tutorial.api.controllers;
 
+import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.web.bind.annotation.PathVariable;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RequestMethod;
 import org.springframework.web.bind.annotation.RestController;
-import tutorial.persistence.models.Product;
 import tutorial.persistence.models.ProductList;
+import tutorial.persistence.repositories.ProductListRepository;
 
-import java.math.BigDecimal;
-import java.util.ArrayList;
 import java.util.List;
 
 @RestController
 public class ProductListController extends ApiController {
 
+    @Autowired
+    ProductListRepository productListRepository;
+
     @RequestMapping(value="/lists", method= RequestMethod.GET)
     public List<ProductList> showAll() {
-        List<ProductList> productLists = new ArrayList<>();
-
-        for (int i = 1; i < 4; i++) {
-            ProductList productList = new ProductList(i, "Tech Goodies (" + i + ")"
-            );
-
-            List<Product> products = new ArrayList<>();
-            products.add(new Product(1, "Macbook Air", new BigDecimal("999.95")));
-            products.add(new Product(2, "Microsoft Surface 3", new BigDecimal("449"
-            )));
-            productList.setProducts(products);
-
-            productLists.add(productList);
-        }
-
-        return productLists;
+        return (List<ProductList>) productListRepository.findAll();
     }
 
     @RequestMapping(value="/lists/{productListId}", method=RequestMethod.GET)
     public ProductList show(@PathVariable("productListId") long productListId) {
-        ProductList productList = new ProductList(productListId, "Tech Goodies (" + productListId + ")");
-
-        List<Product> products = new ArrayList<>();
-        products.add(new Product(1, "Macbook Air", new BigDecimal("999.95")));
-        products.add(new Product(2, "Microsoft Surface 3", new BigDecimal("449")));
-        productList.setProducts(products);
-
-        return productList;
+        return productListRepository.findOne(productListId);
     }
 
-}
+}

src/main/java/tutorial/persistence/models/Product.java

@@ -1,22 +1,31 @@
-// Product.java
 package tutorial.persistence.models;
 
+import com.fasterxml.jackson.annotation.JsonBackReference;
+
+import javax.persistence.*;
 import java.math.BigDecimal;
+import java.util.List;
 
+@Entity
 public class Product {
 
-    private final long id;
-    private final String name;
-    private final BigDecimal price;
+    @Id
+    @GeneratedValue
+    private long id;
 
-    public Product(String name, BigDecimal price) {
-        this.id = -1;
-        this.name = name;
-        this.price = price;
-    }
+    @Column(nullable=false)
+    private String name;
+
+    @Column(nullable=false)
+    private BigDecimal price;
 
-    public Product(long id, String name, BigDecimal price) {
-        this.id = id;
+    @ManyToMany(mappedBy="products")
+    @JsonBackReference
+    private List<ProductList> lists;
+
+    public Product() {}
+
+    public Product(String name, BigDecimal price) {
         this.name = name;
         this.price = price;
     }
@@ -33,4 +42,8 @@ public BigDecimal getPrice() {
         return price;
     }
 
-}
+    public List<ProductList> getLists() {
+        return lists;
+    }
+
+}

src/main/java/tutorial/persistence/models/ProductList.java

@@ -1,21 +1,27 @@
-// ProductList.java
 package tutorial.persistence.models;
 
+import com.fasterxml.jackson.annotation.JsonManagedReference;
+
+import javax.persistence.*;
 import java.util.List;
 
+@Entity
 public class ProductList {
 
-    private final long id;
-    private final String name;
+    @Id
+    @GeneratedValue
+    private long id;
+
+    @Column(nullable=false)
+    private String name;
+
+    @ManyToMany
+    @JsonManagedReference
     private List<Product> products;
 
-    public ProductList(String name) {
-        this.id = -1;
-        this.name = name;
-    }
+    public ProductList() {}
 
-    public ProductList(long id, String name) {
-        this.id = id;
+    public ProductList(String name) {
         this.name = name;
     }
 
@@ -31,8 +37,4 @@ public List<Product> getProducts() {
         return products;
     }
 
-    public void setProducts(List<Product> products) {
-        this.products = products;
-    }
-
-}
+}

src/main/java/tutorial/persistence/repositories/ProductListRepository.java

@@ -0,0 +1,8 @@
+package tutorial.persistence.repositories;
+
+import org.springframework.data.repository.CrudRepository;
+import tutorial.persistence.models.ProductList;
+
+public interface ProductListRepository extends CrudRepository<ProductList, Long> {
+
+}

src/main/java/tutorial/persistence/repositories/ProductRepository.java

@@ -0,0 +1,8 @@
+package tutorial.persistence.repositories;
+
+import org.springframework.data.repository.CrudRepository;
+import tutorial.persistence.models.Product;
+
+public interface ProductRepository extends CrudRepository<Product, Long> {
+
+}

src/main/resources/application.properties

@@ -1 +1,2 @@
-spring.profiles.active=dev
+spring.profiles.active=dev
+spring.jpa.hibernate.ddl-auto=none