Question

我需要将图像上传到数据库（不确定是否最好这样做或上传文件并从数据库中引用它）并且我已经定义了一个表单和一个控制器来执行该操作。问题是我需要将MultipartFile转换为Blob对象，为此我需要使用需要Session对象的Hibernate.getLobCreator。

这是第一次使用基于Java的配置，我有下一个类来定义持久化上下文：

@Configuration
@EnableJpaRepositories(basePackages = {
        "com.davidmogar.alsa"
})
@EnableTransactionManagement
public class PersistenceContext {

    private static final String[] ENTITY_PACKAGES = {
            "com.davidmogar.alsa.domain"
    };

    private static final String PROPERTY_NAME_DB_DRIVER_CLASS = "db.driver";
    private static final String PROPERTY_NAME_DB_PASSWORD = "db.password";
    private static final String PROPERTY_NAME_DB_URL = "db.url";
    private static final String PROPERTY_NAME_DB_USER = "db.username";
    private static final String PROPERTY_NAME_HIBERNATE_DIALECT = "hibernate.dialect";
    private static final String PROPERTY_NAME_HIBERNATE_FORMAT_SQL = "hibernate.format_sql";
    private static final String PROPERTY_NAME_HIBERNATE_HBM2DDL_AUTO = "hibernate.hbm2ddl.auto";
    private static final String PROPERTY_NAME_HIBERNATE_NAMING_STRATEGY =     "hibernate.ejb.naming_strategy";
    private static final String PROPERTY_NAME_HIBERNATE_SHOW_SQL = "hibernate.show_sql";

    @Bean(destroyMethod = "close")
    DataSource dataSource(Environment environment) {
        HikariConfig dataSourceConfig = new HikariConfig();
              dataSourceConfig.setDriverClassName(environment.getRequiredProperty(PROPERTY_NAME_DB_DRIVER_CLASS));
        dataSourceConfig.setJdbcUrl(environment.getRequiredProperty(PROPERTY_NAME_DB_URL));
        dataSourceConfig.setUsername(environment.getRequiredProperty(PROPERTY_NAME_DB_USER));
        dataSourceConfig.setPassword(environment.getRequiredProperty(PROPERTY_NAME_DB_PASSWORD));

        return new HikariDataSource(dataSourceConfig);
    }

    @Bean(name = "entityManagerFactory")
    LocalContainerEntityManagerFactoryBean entityManagerFactoryBean(DataSource dataSource, Environment environment) {
        LocalContainerEntityManagerFactoryBean entityManagerFactoryBean = new LocalContainerEntityManagerFactoryBean();
        entityManagerFactoryBean.setDataSource(dataSource);
        entityManagerFactoryBean.setJpaVendorAdapter(new HibernateJpaVendorAdapter());
        entityManagerFactoryBean.setPackagesToScan(ENTITY_PACKAGES);

        Properties jpaProperties = new Properties();

        jpaProperties.put(PROPERTY_NAME_HIBERNATE_DIALECT, environment.getRequiredProperty
                (PROPERTY_NAME_HIBERNATE_DIALECT));

        jpaProperties.put(PROPERTY_NAME_HIBERNATE_HBM2DDL_AUTO, environment.getRequiredProperty
                (PROPERTY_NAME_HIBERNATE_HBM2DDL_AUTO));

        jpaProperties.put(PROPERTY_NAME_HIBERNATE_NAMING_STRATEGY, environment.getRequiredProperty
                (PROPERTY_NAME_HIBERNATE_NAMING_STRATEGY));

        jpaProperties.put(PROPERTY_NAME_HIBERNATE_SHOW_SQL, environment.getRequiredProperty
                (PROPERTY_NAME_HIBERNATE_SHOW_SQL));

        jpaProperties.put(PROPERTY_NAME_HIBERNATE_FORMAT_SQL, environment.getRequiredProperty
                (PROPERTY_NAME_HIBERNATE_FORMAT_SQL));

        entityManagerFactoryBean.setJpaProperties(jpaProperties);

        return entityManagerFactoryBean;
    }

    @Bean
    JpaTransactionManager transactionManager(EntityManagerFactory entityManagerFactory) {
        JpaTransactionManager transactionManager = new JpaTransactionManager();
        transactionManager.setEntityManagerFactory(entityManagerFactory);

        return transactionManager;
    }

}

如何在控制器中获取会话以转换MultipartFile？

Answer 1

您可以通过EntityManager获取Hibernate Session的实例。

@Autowired
private EntityManagerFactory emf;

public void foo(){
EntityManager em = emf.createEntityManager();
Session session = em.unwrap(Session.class);
LobCreator lob = getLobCreator(session);
...
}

在基于Java的Spring App上获取SessionFactory

1 个答案: