Przykłady odczytu pojedynczych rekordów

PC27-Hibernate/src/main/java/META-INF/persistence.xml

 <?xml version="1.0" encoding="UTF-8"?>
 <persistence version="2.2" xmlns="http://xmlns.jcp.org/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence http://xmlns.jcp.org/xml/ns/persistence/persistence_2_2.xsd">
-	<persistence-unit name="PC27-Hibernate">
+	<persistence-unit name="sklep" transaction-type="RESOURCE_LOCAL">
 		<class>sklep.model.Customer</class>
 		<class>sklep.model.OrderProduct</class>
 		<class>sklep.model.OrderProductPK</class>
 		<class>sklep.model.Order</class>
 		<class>sklep.model.Product</class>
+		<properties>
+			<property name="javax.persistence.jdbc.url" value="jdbc:postgresql://localhost:5432/sklep"/>
+			<property name="javax.persistence.jdbc.user" value="kurs"/>
+			<property name="javax.persistence.jdbc.password" value="abc123"/>
+			<property name="javax.persistence.jdbc.driver" value="org.postgresql.Driver"/>
+			<property name="hibernate.show_sql" value="true"/>
+		</properties>
 	</persistence-unit>
 </persistence>

PC27-Hibernate/src/main/java/przyklady/Odczyt1_JedenProdukt.java

+package przyklady;
+
+import javax.persistence.EntityManager;
+import javax.persistence.EntityManagerFactory;
+import javax.persistence.Persistence;
+
+import sklep.model.Product;
+
+public class Odczyt1_JedenProdukt {
+
+	public static void main(String[] args) {
+		EntityManagerFactory emf = Persistence.createEntityManagerFactory("sklep");
+		EntityManager em = emf.createEntityManager();
+		System.out.println("Udało się połączyć, em = " + em);
+		
+		Product product = em.find(Product.class, 1);
+		System.out.println("Odczytany produkt: " + product);
+		System.out.println(product.getProductName() + " za cenę " + product.getPrice());
+		em.close();
+		emf.close();
+	}
+
+}

PC27-Hibernate/src/main/java/przyklady/Odczyt2_Petla.java

+package przyklady;
+
+import java.util.Scanner;
+
+import javax.persistence.EntityManager;
+import javax.persistence.EntityManagerFactory;
+import javax.persistence.Persistence;
+
+import sklep.model.Product;
+
+public class Odczyt2_Petla {
+
+	public static void main(String[] args) {
+		Scanner scanner = null;
+		EntityManagerFactory emf = null;
+		EntityManager em = null;
+		try {
+			scanner = new Scanner(System.in);
+			emf = Persistence.createEntityManagerFactory("sklep");
+			em = emf.createEntityManager();
+			
+			while(true) {
+				System.out.print("\nPodaj id produktu: ");
+				int productId = scanner.nextInt();
+				if(productId == 0) break;
+				
+				Product product = em.find(Product.class, productId);
+				if(product == null) {
+					System.out.println("Nie ma takiego produktu");
+					continue;
+				}
+				System.out.println("Odczytany produkt: " + product);
+				System.out.println(product.getProductName() + " za cenę " + product.getPrice());
+				if(product.getDescription() != null) {
+					System.out.println(product.getDescription());
+				}
+			}
+		} finally {
+			if(em != null) em.close();
+			if(emf != null) emf.close();
+			if(scanner != null) scanner.close();
+		}
+	}
+
+}

PC27-Hibernate/src/main/java/sklep/model/OrderProduct.java

@@ -28,12 +28,12 @@ public class OrderProduct extends WspolnaNadklasa implements Serializable {
 
 	//bi-directional many-to-one association to Order
 	@ManyToOne
-	@JoinColumn(name="order_id")
+	@JoinColumn(name="order_id", insertable=false, updatable=false)
 	private Order order;
 
 	//uni-directional many-to-one association to Product
 	@ManyToOne
-	@JoinColumn(name="product_id")
+	@JoinColumn(name="product_id", insertable=false, updatable=false)
 	private Product product;
 
 	public OrderProduct() {