@Entity
@Table(name = "users")
public class User {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
private String name;
private int age;
}
public interface UserDao {
User findById(Long id);
List<User> findAll();
void save(User user);
}
@Repository
public class UserDaoImpl implements UserDao {
@PersistenceContext
private EntityManager entityManager;
@Override
public User findById(Long id) {
return entityManager.find(User.class, id);
}
@Override
public List<User> findAll() {
CriteriaBuilder cb = entityManager.getCriteriaBuilder();
CriteriaQuery<User> cq = cb.createQuery(User.class);
Root<User> rootEntry = cq.from(User.class);
CriteriaQuery<User> all = cq.select(rootEntry);
TypedQuery<User> allQuery = entityManager.createQuery(all);
return allQuery.getResultList();
}
@Override
public void save(User user) {
entityManager.persist(user);
}
}
<persistence xmlns="http://xmlns.jcp.org/xml/ns/persistence"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
version="2.2"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence
http://xmlns.jcp.org/xml/ns/persistence/persistence_2_2.xsd">
<persistence-unit name="my-persistence-unit" transaction-type="RESOURCE_LOCAL">
<provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>
<class>com.example.User</class>
<properties>
<property name="javax.persistence.jdbc.url" value="jdbc:mysql://localhost:3306/mydatabase"/>
<property name="javax.persistence.jdbc.user" value="root"/>
<property name="javax.persistence.jdbc.password" value="password"/>
<property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver"/>
</properties>
</persistence-unit>
</persistence>
