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

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

使用注解@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 Kartoch 提供的 Java 配置之外，您还可以在 spring 上下文 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）？

How to initialize an EntityManager with the help of Springs (without using persistent.xml file)?

java

spring

jpa