我试图找出集成 Hibernate 和 Spring Data JPA 的新机制。我按照https://www.baeldung.com/hibernate-5-spring上提供的示例进行操作,但无济于事。进一步的研究给我带来了Juergen Hoeller在 Github 上的一个问题,他说:
[...] 这涵盖了很多开始的基础:在 Hibernate 5.2 和 5.3 中,LocalSessionFactoryBean 和 HibernateTransactionManager 在许多场景中充当 LocalContainerEntityManagerFactoryBean 和 JpaTransactionManager 的 99% 兼容替代品,允许与 SessionFactory.getCurrentSession() 交互(还有 HibernateTemplate) 在同一本地事务中的 @PersistenceContext EntityManager 交互旁边 (#21454)。除此之外,这样的设置还提供了更强大的 Hibernate 集成(#21494、#20852)和更多的配置灵活性,不受 JPA 引导合同的限制。
LocalSessionFactoryBean类的相应 Javadoc说明:
从 Spring 5.1 开始,与 Hibernate 5.0/5.1 以及 5.2/5.3 兼容。使用 Hibernate 5.3 设置,LocalSessionFactoryBean 是 LocalContainerEntityManagerFactoryBean 的直接替代品,用于常见的 JPA 目的:特别是在 Hibernate 5.3 中,Hibernate SessionFactory 也将本机公开 JPA EntityManagerFactory 接口,并且 Hibernate BeanContainer 集成将开箱即用地注册。结合 HibernateTransactionManager,这自然允许在同一事务中混合 JPA 访问代码和本机 Hibernate 访问代码。
我使用 Spring Boot 2.1.2.RELEASE 实现了一个简单的示例项目。它提供了一个简单的配置(与上面的 Baeldung 示例相同)并连接到 PostgreSQL 数据库。此外,从理论上讲,它使用模型和存储库来处理数据。这些类看起来像这样:
DemoApplication.java
package com.example.demo;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
public class DemoApplication
{
public static void main(String[] args)
{
SpringApplication.run(DemoApplication.class, args);
}
}
基本配置.java
package com.example.demo;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;
import org.springframework.data.repository.config.BootstrapMode;
import org.springframework.jdbc.datasource.SimpleDriverDataSource;
import org.springframework.orm.hibernate5.HibernateTransactionManager;
import org.springframework.orm.hibernate5.LocalSessionFactoryBean;
import org.springframework.transaction.PlatformTransactionManager;
import javax.sql.DataSource;
import org.postgresql.Driver;
import java.util.Properties;
@Configuration
@EnableJpaRepositories
public class BasicConfig
{
@Bean
public LocalSessionFactoryBean sessionFactory()
{
LocalSessionFactoryBean sessionFactory = new LocalSessionFactoryBean();
sessionFactory.setDataSource(dataSource());
sessionFactory.setPackagesToScan("com.example.demo");
sessionFactory.setHibernateProperties(hibernateProperties());
return sessionFactory;
}
@Bean
public DataSource dataSource()
{
SimpleDriverDataSource dataSource = new SimpleDriverDataSource();
dataSource.setDriverClass(Driver.class);
dataSource.setUrl("jdbc:postgresql://localhost:5432/backend");
dataSource.setUsername("backend");
dataSource.setPassword("backend");
return dataSource;
}
@Bean
public PlatformTransactionManager hibernateTransactionManager()
{
HibernateTransactionManager transactionManager
= new HibernateTransactionManager();
transactionManager.setSessionFactory(sessionFactory().getObject());
return transactionManager;
}
private final Properties hibernateProperties()
{
Properties hibernateProperties = new Properties();
hibernateProperties.setProperty(
"hibernate.hbm2ddl.auto", "create-drop");
hibernateProperties.setProperty(
"hibernate.dialect", "org.hibernate.dialect.PostgreSQL95Dialect");
return hibernateProperties;
}
}
模型.java
package com.example.demo;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Table;
@Entity
@Table(name = "model")
public class Model
{
@Id
@GeneratedValue
@Column(name = "id", unique = true, nullable = false)
private Long id;
@Column(name = "name")
private String name;
}
DemoRepository.java
package com.example.demo;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;
@Repository
public interface DemoRepository extends JpaRepository<Model, Long>
{
}
一旦我添加了DemoRepository
应用程序就不再启动,因为:
A component required a bean named 'entityManagerFactory' that could not be found.
Action:
Consider defining a bean named 'entityManagerFactory' in your configuration.
完整的错误信息:
Exception encountered during context initialization - cancelling refresh
attempt: org.springframework.beans.factory.BeanCreationException:
Error creating bean with name 'demoRepository':
Cannot create inner bean '(inner bean)#6c5ca0b6' of type [org.springframework.orm.jpa.SharedEntityManagerCreator]
while setting bean property 'entityManager';
nested exception is org.springframework.beans.factory.BeanCreationException:
Error creating bean with name '(inner bean)#6c5ca0b6':
Cannot resolve reference to bean 'entityManagerFactory' while setting constructor argument;
nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException:
No bean named 'entityManagerFactory' available
我的印象是,SessionFactory
现在正确实施并公开了,EntityManagerFactory
但似乎并非如此。我很确定我的实现存在缺陷,并且来自 Baeldung 的示例实际上可以正常工作。我希望有人可以向我指出并帮助我理解我的错误。
提前感谢大家。
依赖项:
- spring-data-jpa:2.1.4.RELEASE
- 弹簧芯:5.1.4.RELEASE
- spring-orm:5.1.4.RELEASE
- 休眠核心:5.3.7.Final
- 弹簧启动:2.1.2.RELEASE
gradle.build
buildscript {
ext {
springBootVersion = '2.1.2.RELEASE'
}
repositories {
mavenCentral()
}
dependencies {
classpath("org.springframework.boot:spring-boot-gradle-plugin:${springBootVersion}")
}
}
apply plugin: 'java'
apply plugin: 'org.springframework.boot'
apply plugin: 'io.spring.dependency-management'
group = 'com.example'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = '11'
repositories {
mavenCentral()
}
dependencies {
implementation 'org.springframework.boot:spring-boot-starter-data-jpa'
implementation 'org.postgresql:postgresql'
}