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Tutorials > Spring > Data access with Spring using JDBC, Hibernate, and JPA

Data access with Spring using JDBC, Hibernate, and JPA

Spring provides several options for data access, including JDBC, Hibernate, and JPA. Each option has its own strengths and weaknesses, and the choice of which one to use depends on the specific requirements of the application.

JDBC (Java Database Connectivity) is a low-level API that provides a standard way to access databases in Java. Spring provides a convenient abstraction over JDBC, making it easier to work with databases and reducing the amount of boilerplate code required.

Example using JDBC:

@Autowired
private JdbcTemplate jdbcTemplate;

public List<Employee> getEmployees() {
  return jdbcTemplate.query("SELECT * FROM employees", (rs, rowNum) ->
      new Employee(rs.getInt("id"), rs.getString("name"), rs.getString("email"))
  );
}

In the example above, the JdbcTemplate is used to execute a SQL query to retrieve all employees from the database. The query results are then mapped to a list of Employee objects using a lambda expression.

Hibernate is a popular ORM (Object-Relational Mapping) framework that provides a convenient way to work with databases and maps the relational database structure to Java objects. Spring provides support for Hibernate, making it easy to integrate Hibernate into a Spring application.

Example using Hibernate:

@Repository
public class EmployeeDaoImpl implements EmployeeDao {

  @Autowired
  private SessionFactory sessionFactory;

  @Override
  public List<Employee> getEmployees() {
    Session session = sessionFactory.getCurrentSession();
    return session.createQuery("from Employee", Employee.class).list();
  }

}

In the example above, the SessionFactory is used to obtain a Session object, which is used to execute a HQL (Hibernate Query Language) query to retrieve all employees from the database. The query results are then mapped to a list of Employee objects.

JPA (Java Persistence API) is a Java specification for accessing, persisting, and managing data between Java objects/classes and relational databases. Spring provides support for JPA, making it easy to integrate JPA into a Spring application.

Example using JPA:

@Repository public class EmployeeDaoImpl implements EmployeeDao { @PersistenceContext private EntityManager entityManager; @Override public List<Employee> getEmployees() { return entityManager.createQuery("from Employee", Employee.class).getResultList(); } 
}

In the example above, the EntityManager is used to execute a JPQL (Java Persistence Query Language) query to retrieve all employees from the database. The query results are then mapped to a list of Employee objects using the getResultList method.

Each of these options provides a different level of abstraction over the database and can be used depending on the specific requirements of the application. Spring provides support for all of these options, making it easy to choose the right option for the application and integrate it with the rest of the application.



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