Hibernate und JPA

package at.aydin.lab.hibernate.legacy;

import javax.persistence.*;

@Entity
@Table(name = "book")
public class LegacyBook {
    @Id
    @GeneratedValue
    private Long id;
    private String title;
    protected LegacyBook() {
    }

    public LegacyBook(String title) {
        this.title = title;
    }

    public Long getId() {
        return id;
    }

    public String getTitle() {
        return title;
    }
}

package at.aydin.lab.hibernate.modern;

import jakarta.persistence.*;

@Entity
@Table(name = "book")
public class BookEntity {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    private String title;
    protected BookEntity() {
    }

    public BookEntity(String title) {
        this.title = title;
    }

    public Long getId() {
        return id;
    }

    public String getTitle() {
        return title;
    }
}

package at.aydin.lab.hibernate.legacy;

import org.hibernate.*;
import org.hibernate.cfg.Configuration;
import java.util.*;

// Design Pattern: Unit of Work
// Zweck: Hibernate Session und Transaction bilden eine explizite Arbeitseinheit.
public final class HibernateBookStore implements AutoCloseable {
    private final SessionFactory factory = new Configuration().addAnnotatedClass(LegacyBook.class).setProperty("hibernate.connection.url",
        "jdbc:h2:mem:hibernatelegacy;DB_CLOSE_DELAY=-1").setProperty("hibernate.connection.driver_class", "org.h2.Driver")
            .setProperty("hibernate.dialect", "org.hibernate.dialect.H2Dialect").setProperty("hibernate.hbm2ddl.auto", "create-drop")
            .buildSessionFactory();
    public Long save(String title) {
        try (Session s = factory.openSession()) {
            Transaction tx = s.beginTransaction();
            Long id = (Long) s.save(new LegacyBook(title));
            tx.commit();
            return id;
        }
    }

    public Optional<LegacyBook> find(Long id) {
        try (Session s = factory.openSession()) {
            return Optional.ofNullable(s.get(LegacyBook.class, id));
        }
    }

    public void close() {
        factory.close();
    }
}

package at.aydin.lab.hibernate.modern;

import org.springframework.data.jpa.repository.JpaRepository;

// Design Pattern: Repository
// Zweck: Datenzugriff wird als deklarativer fachlicher Vertrag ausgedrückt.
public interface BookRepository extends JpaRepository<BookEntity, Long> {
}

package at.aydin.lab.hibernate.legacy;

import javax.persistence.*;

@Entity
@Table(name = "book")
public class LegacyBook {
    @Id
    @GeneratedValue
    private Long id;
    private String title;
    protected LegacyBook() {
    }

    public LegacyBook(String title) {
        this.title = title;
    }

    public Long getId() {
        return id;
    }

    public String getTitle() {
        return title;
    }
}

package at.aydin.lab.hibernate.modern;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class JpaModernApplication {
    public static void main(String[] args) {
        SpringApplication.run(JpaModernApplication.class, args);
    }
}