Parametry JPQL

src/main/java/przyklady/P5_Parametry.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.math.BigDecimal;
+import java.util.List;
+import java.util.Scanner;
+
+public class P5_Parametry {
+    public static void main(String[] args) {
+        Scanner scanner = new Scanner(System.in);
+
+        try(EntityManagerFactory emf = Persistence.createEntityManagerFactory("hr");
+            EntityManager em = emf.createEntityManager()) {
+
+            System.out.print("Podaj dwie liczby, zakres pensji: ");
+            BigDecimal min = scanner.nextBigDecimal();
+            BigDecimal maks = scanner.nextBigDecimal();
+            scanner.nextLine();
+
+            // JPQL = Jakarta Persistence Query Language
+            // Jak SQL, ale na poziomie obiektów, z pewnymi różnicami i ograniczeniami.
+            // Parametry wpisuje się za pomocą :nazwa
+            final String select1 = "SELECT e FROM Employee e WHERE e.salary BETWEEN :min AND :max ORDER BY e.salary DESC";
+            TypedQuery<Employee> query1 = em.createQuery(select1, Employee.class);
+            query1.setParameter("min", min);
+            query1.setParameter("max", maks);
+            List<Employee> employees = query1.getResultList();
+
+            System.out.println("Odczytano " + employees.size() + " rekordów.");
+            for(Employee employee : employees) {
+                System.out.println(employee.getFirstName() + " " + employee.getLastName()
+                        + " (" + employee.getJob().getJobTitle() + "): " + employee.getSalary());
+            }
+
+            System.out.print("Podaj miasto: ");
+            String city = scanner.nextLine();
+            final String select2 = "SELECT e FROM Employee e WHERE e.department.location.city = :city";
+            TypedQuery<Employee> query2 = em.createQuery(select2, Employee.class);
+            query2.setParameter("city", city);
+            query2.getResultStream()
+                    .map(emp -> emp.getFirstName() + " " + emp.getLastName())
+                    .forEach(System.out::println);
+        }
+    }
+}