Odczyty wszystkich rekordów

src/main/java/hr/model/AbstractEntity.java

@@ -29,7 +29,7 @@ abstract class AbstractEntity {
                 }
                 Object value = "";
                 if(Collection.class.isAssignableFrom(field.getType())) {
-                    value = "[]";
+                    value = "[…]";
                 } else if(field.trySetAccessible()) {
                     value = field.get(this);
                 } else {

src/main/java/hr/model/Employee.java

@@ -7,6 +7,11 @@ import java.time.LocalDate;
 
 @Entity
 @Table(name = "employees")
+
+@NamedQueries({
+    @NamedQuery(name="Employee.findAll", query="SELECT e FROM Employee e ORDER BY e.id"),
+    @NamedQuery(name="Employee.findByLastName", query="SELECT e FROM Employee e WHERE e.lastName = :lastName ORDER BY e.id"),
+})
 public class Employee extends AbstractEntity {
     @Id
     @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "employees_id_gen")

src/main/java/hr/model/Location.java

@@ -5,6 +5,7 @@ import org.hibernate.annotations.ColumnDefault;
 
 @Entity
 @Table(name = "locations")
+@NamedQuery(name = "Location.findAll", query = "SELECT loc FROM Location loc ORDER BY loc.country.id, loc.city")
 public class Location extends AbstractEntity {
     @Id
     @GeneratedValue(strategy = GenerationType.IDENTITY)
@@ -24,7 +25,7 @@ public class Location extends AbstractEntity {
     @Column(name = "state_province", length = 25)
     private String stateProvince;
 
-    @ManyToOne(fetch = FetchType.EAGER)
+    @ManyToOne
     @JoinColumn(name = "country_id")
     private Country country;
 

src/main/java/przyklady/P1_OdczytajPracownika.java

@@ -16,11 +16,12 @@ public class P1_OdczytajPracownika {
             EntityManager em = emf.createEntityManager()) {
 
             while(true) {
-                System.out.print("Podaj id pracownika: ");
+                System.out.print("\nPodaj id pracownika: ");
                 int id = sc.nextInt();
                 if(id < 0) break;
                 Employee employee = em.find(Employee.class, id);
                 System.out.println(employee);
+                System.out.println();
                 // w przypadku braku takiego obiektu wynikiem jest null
                 if(employee != null) {
                     System.out.println(employee.getFirstName()
@@ -29,7 +30,6 @@ public class P1_OdczytajPracownika {
                     System.out.println("Job: " + job + " " + job.getJobId() + " = " + job.getJobTitle());
                     Department dep = employee.getDepartment();
                     if(dep != null) {
-                        System.out.println("a kuku");
                         System.out.println("Klasa obiektu Department: " + dep.getClass().getName());
                         // w przypadku zależności LAZY, dopiero teraz zostaną wczytane szczegóły departamentu
                         System.out.println("Department: " + dep.getDepartmentName());

src/main/java/przyklady/P2_OdczytajWszystkich_JPQL.java

+package przyklady;
+
+import hr.model.Department;
+import hr.model.Employee;
+import hr.model.Job;
+import jakarta.persistence.EntityManager;
+import jakarta.persistence.EntityManagerFactory;
+import jakarta.persistence.Persistence;
+import jakarta.persistence.TypedQuery;
+
+import java.util.List;
+import java.util.Scanner;
+
+public class P2_OdczytajWszystkich_JPQL {
+    public static void main(String[] args) {
+        try(EntityManagerFactory emf = Persistence.createEntityManagerFactory("hr");
+            EntityManager em = emf.createEntityManager()) {
+
+            // JPQL = Jakarta Persistence Query Language
+            // Jak SQL, ale na poziomie obiektów, z pewnymi różnicami i ograniczeniami.
+            TypedQuery<Employee> query = em.createQuery("SELECT e FROM Employee e", Employee.class);
+            List<Employee> employees = query.getResultList();
+
+            System.out.println("Odczytano " + employees.size() + " rekordów.");
+            for(Employee employee : employees) {
+                System.out.println(employee.getFirstName() + " " + employee.getLastName()
+                        + " (" + employee.getJob().getJobTitle() + "): " + employee.getSalary());
+            }
+
+        }
+    }
+}

src/main/java/przyklady/P3_OdczytajWszystkich_NamedQuery.java

+package przyklady;
+
+import hr.model.Employee;
+import jakarta.persistence.EntityManager;
+import jakarta.persistence.EntityManagerFactory;
+import jakarta.persistence.Persistence;
+import jakarta.persistence.TypedQuery;
+
+import java.util.List;
+
+public class P3_OdczytajWszystkich_NamedQuery {
+    public static void main(String[] args) {
+        try(EntityManagerFactory emf = Persistence.createEntityManagerFactory("hr");
+            EntityManager em = emf.createEntityManager()) {
+
+            TypedQuery<Employee> query = em.createNamedQuery("Employee.findAll", Employee.class);
+            List<Employee> employees = query.getResultList();
+
+            System.out.println("Odczytano " + employees.size() + " rekordów.");
+            for(Employee employee : employees) {
+                System.out.println(employee.getFirstName() + " " + employee.getLastName()
+                        + " (" + employee.getJob().getJobTitle() + "): " + employee.getSalary());
+            }
+
+        }
+    }
+}

src/main/java/przyklady/P4_OdczytajWszystkich_Stream.java

+package przyklady;
+
+import jakarta.persistence.EntityManager;
+import jakarta.persistence.EntityManagerFactory;
+import jakarta.persistence.Persistence;
+import hr.model.Location;
+
+public class P4_OdczytajWszystkich_Stream {
+
+    public static void main(String[] args) {
+        // Zapis z użyciem strumienia może dać lepszą wydajność. Zwróć uwagę na kolejność wykonywania dodatkowych selectów
+        try(EntityManagerFactory emf = Persistence.createEntityManagerFactory("hr");
+            EntityManager em = emf.createEntityManager()) {
+            em.createNamedQuery("Location.findAll", Location.class)
+                    .getResultStream()
+                    .map(loc -> String.format(" - %s, %s %s, %s", loc.getStreetAddress(), loc.getPostalCode(), loc.getCity(),
+                            loc.getCountry().getCountryName()))
+                    .forEach(System.out::println);
+        }
+    }
+
+}