关于使用Hibernate 5.3，Spring Data JPA 2.1.4和Spring 5.1的EntityManagerFactory和SessionFactory的困惑

问题描述 投票：0回答：1

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提供的例子，但无济于事。进一步的研究为我带来了Juergen Hoeller的issue on Github说：

[...]这包括很多开始：使用Hibernate 5.2和5.3，LocalSessionFactoryBean和HibernateTransactionManager在许多情况下充当LocalContainerEntityManagerFactoryBean和JpaTransactionManager的99％兼容替代品，允许与SessionFactory.getCurrentSession（）进行交互（以及同一本地事务中的@PersistenceContext EntityManager交互旁边的HibernateTemplate（＃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，而不受JPA引导程序合同的约束。

和LocalSessionFactoryBean类对应的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进行设置，LocalSessionFactoryBean是LocalContainerEntityManagerFactoryBean的直接替代品，用于常见的JPA目的：特别是对于Hibernate 5.3，Hibernate SessionFactory本身也会公开JPA EntityManagerFactory接口，并且Hibernate BeanContainer集成将立即注册。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，它在理论上使用模型和存储库来处理数据。这些类看起来像这样：

demo application.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);
    }
}

BASIC config.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;
    }
}

model.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;
}

demo repository.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，App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.

完整的错误消息：

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SessionFactorynow正确地实施并暴露了EntityManagerFactory，但似乎并非如此。我很确定我的实现存在缺陷，并且Baeldung的示例实际上正常工作。我希望有人可以向我指出并帮助我理解我的错误。 感谢大家提前。

依赖关系：

  • 弹簧数据JPA：2.1.4.RELEASE
  • 弹簧核心：5.1.4.RELEASE
  • 弹簧ORM：5.1.4.RELEASE
  • 休眠核心：5.3.7.Final
  • 春季启动：2.1.2.RELEASE

grad了.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'
}
hibernate spring-data-jpa spring-data hibernate-5.x hibernate-5
1个回答
0
投票

经过一些反复试验，我们发现配置有什么问题。以下（删节）配置有效：

@Configuration
@EnableJpaRepositories(
        basePackages = "com.example.repository",
        bootstrapMode = BootstrapMode.DEFERRED
)
@EnableTransactionManagement
@Profile({ "local", "dev", "prod" })
public class DatabaseConfig
{
    @Bean
    public LocalSessionFactoryBean entityFactoryBean(
            final DataSource dataSource
    )
    {
        final LocalSessionFactoryBean sessionFactory = new LocalSessionFactoryBean();

        sessionFactory.setDataSource(dataSource);
        sessionFactory.setPackagesToScan("com.example.model");

        return sessionFactory;
    }

    @Bean
    public PersistenceExceptionTranslationPostProcessor exceptionTranslation()
    {
        return new PersistenceExceptionTranslationPostProcessor();
    }

    @Bean
    public HibernateTransactionManager transactionManager(
            final SessionFactory sessionFactory,
            final DataSource dataSource
    )
    {
        final HibernateTransactionManager transactionManager = new HibernateTransactionManager();

        transactionManager.setSessionFactory(sessionFactory);
        transactionManager.setDataSource(dataSource);

        return transactionManager;
    }
}

LocalSessionFactoryBean可以命名为entityFactoryBean，而Spring仍然可以为SessionFactoy自动装配hibernateTransactionManager。我希望如果其他人有类似的问题，这会有所帮助。

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