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Hibernate

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Introduce

Hibernate is a ORM framework that implementes the JPA API.

Use Hibernate

Configure Data Source

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@Configuration
@ComponentScan
@EnableTransactionManagement
@PropertySource("jdbc.properties")
public class AppConfig {
    @Bean
    DataSource createDataSource() {
        ...
    }
}

Create SessionFactory

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public class AppConfig {
    @Bean
    LocalSessionFactoryBean createSessionFactory(@Autowired DataSource dataSource) {
        var props = new Properties();
        props.setProperty("hibernate.hbm2ddl.auto", "update");
        props.setProperty("hibernate.dialect", "org.hibernate.dialect.HSQLDialect");
        props.setProperty("hibernate.show_sql", "true");
        var sessionFactoryBean = new LocalSessionFactoryBean();
        sessionFactoryBean.setDataSource(dataSource);
        // Scan package to get entity class:
        sessionFactoryBean.setPackagesToScan("com.itranswarp.learnjava.entity");
        sessionFactoryBean.setHibernateProperties(props);
        return sessionFactoryBean;
    }

    @Bean
    HibernateTemplate createHibernateTemplate(@Autowired SessionFactory sessionFactory) {
        return new HibernateTemplate(sessionFactory);
    }

    @Bean
    PlatformTransactionManager createTxManager(@Autowired SessionFactory sessionFactory) {
        return new HibernateTransactionManager(sessionFactory);
    }
}

Create Entity Class

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@Entity
@Table(name = "...")
public class User {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(nullable = false, updatable = false)
    public Long getId() { ... }

    @Column(nullable = false, unique = true, length = 100)
    public String getEmail() { ... }

    @Column(nullable = false, length = 100)
    public String getPassword() { ... }

    @Column(nullable = false, length = 100)
    public String getName() { ... }

    @Column(nullable = false, updatable = false)
    public Long getCreatedAt() { ... }
}

Save Entity

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public User register(String email, String password, String name) {
    User user = new User();
    user.setEmail(email);
    user.setPassword(password);
    user.setName(name);
    // Don't need to set id.s
    hibernateTemplate.save(user);
    System.out.println(user.getId());
    return user;
}