Question

如何在Springs的帮助下初始化实体管理器（不使用persistent.xml文件）？

Answer 1

使用注释@Configuration：

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;
import org.springframework.jdbc.datasource.DriverManagerDataSource;
import org.springframework.orm.jpa.JpaTransactionManager;
import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;
import org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter;
import org.springframework.transaction.PlatformTransactionManager;
import org.springframework.transaction.annotation.EnableTransactionManagement;
import javax.sql.DataSource;

@Configuration
@EnableTransactionManagement
@ComponentScan(basePackages = "fr.plil.sio.jpa")
@EnableJpaRepositories("fr.plil.sio.jpa")
public class JpaAppConfiguration {

    @Bean
    public DataSource dataSource() {
        DriverManagerDataSource dataSource = new DriverManagerDataSource();
        dataSource.setDriverClassName("org.h2.Driver");
        dataSource.setUrl("jdbc:h2:mem:jpa_example;TRACE_LEVEL_FILE=4;DB_CLOSE_DELAY=-1;DB_CLOSE_ON_EXIT=FALSE");
        dataSource.setUsername("foo");
        dataSource.setPassword("bar");
        return dataSource;
    }

    @Bean
    public LocalContainerEntityManagerFactoryBean entityManagerFactory() {
        HibernateJpaVendorAdapter vendorAdapter = new HibernateJpaVendorAdapter();
        vendorAdapter.setGenerateDdl(true);
        vendorAdapter.setDatabasePlatform("org.hibernate.dialect.H2Dialect");
        vendorAdapter.setShowSql(true);
        LocalContainerEntityManagerFactoryBean factory =
                new LocalContainerEntityManagerFactoryBean();
        factory.setJpaVendorAdapter(vendorAdapter);
        factory.setDataSource(dataSource());
        factory.setPackagesToScan("fr.plil.sio.jpa");
        return factory;
    }

    @Bean
    public PlatformTransactionManager transactionManager() {
        JpaTransactionManager txManager = new JpaTransactionManager();
        txManager.setEntityManagerFactory(entityManagerFactory().getObject());
        return txManager;
    }
}

Answer 2

您可以使用此Spring bean org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean并将packagesToScan属性设置为指向包含您的实体的包。请注意，除了上面的Kartoch提供的Java配置之外，您还可以在spring context xml文件中配置此bean。

如何在Springs的帮助下初始化EntityManager（不使用persistent.xml文件）？

2 个答案: