java - 我需要如何配置 PersistenceJPAConfig？

Question

我有一堂带有配置的类(class)。我有一个方法entityManagerFactory()，标记为Bean。

@Configuration
@EnableTransactionManagement
@PropertySource({ "classpath:hibernate.properties" })
@EnableJpaRepositories
public class PersistenceJPAConfig {
    @Bean
    public LocalContainerEntityManagerFactoryBean entityManagerFactory() {
        LocalContainerEntityManagerFactoryBean em = new LocalContainerEntityManagerFactoryBean();
        em.setDataSource(dataSource());
        em.setPackagesToScan(new String[] { "java.entities" });

    JpaVendorAdapter vendorAdapter = new HibernateJpaVendorAdapter();
    em.setJpaVendorAdapter(vendorAdapter);
    em.setJpaProperties(additionalProperties());

    return em;
}

@Bean
public DataSource dataSource(){
    DriverManagerDataSource dataSource = new DriverManagerDataSource();
    dataSource.setDriverClassName("com.mysql.cj.jdbc.Driver");
    dataSource.setUrl("jdbc:mysql://localhost:3306/carpark?useUnicode=true&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=UTCx`");
    dataSource.setUsername( "root" );
    dataSource.setPassword( "1111" );
    return dataSource;
}

@Bean
public PlatformTransactionManager transactionManager(EntityManagerFactory emf){
    JpaTransactionManager transactionManager = new JpaTransactionManager();
    transactionManager.setEntityManagerFactory(emf);

    return transactionManager;
}

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

public Properties additionalProperties() {
    Properties properties = new Properties();
    properties.setProperty("hibernate.hbm2ddl.auto", "update");
    properties.setProperty("hibernate.dialect", "org.hibernate.dialect.MySQL5Dialect");
    return properties;
}

}

我有一个使用 EntityManager 的服务。 EntityManager 标记为 @Autowired，并且 spring create EntityManager 为 null。我哪里配置不正确。我需要使用来自方法entityManagerFactory()(在类PersistenceJPAConfig中)的字段的entityManager。

@Service
public class BusService {
@Autowired
private BusRepository busRepository;

@Autowired
private EntityManager entityManager;


public void getBus(){
    try{
       entityManager.getTransaction().begin();
       Query query = entityManager.createNativeQuery("SELECT ID, NUMBER , Rote_ID FROM bus", Bus.class);
       busRepository.save(query.getResultList());
       System.out.println(busRepository.toString());
   }finally {
       entityManager.getTransaction().commit();
   }
}

}

我的包裹位于这样的位置

提前致谢

Answer 1

您应该使用“@PersistenceContext”注释来注入(inject)实体管理器:

@Service
public class BusService {
@Autowired
private BusRepository busRepository;

@PersistenceContext
private EntityManager entityManager;

public void getBus(){
  try{
    entityManager.getTransaction().begin();
    Query query = entityManager.createNativeQuery("SELECT ID, NUMBER , Rote_ID FROM bus", Bus.class);
   busRepository.save(query.getResultList());
   System.out.println(busRepository.toString());
  } finally {
    entityManager.getTransaction().commit();
  }
}

这样做有几个原因，您可以获取概述 here

并使用@ComponentScan注释更新您的配置类

@Configuration
@EnableTransactionManagement
@PropertySource({ "classpath:hibernate.properties" })
@EnableJpaRepositories
@ComponentScan(basePackages = {
    "model.service"})
public class PersistenceJPAConfig {

   ....

   @Bean
   public LocalContainerEntityManagerFactoryBean entityManagerFactory() { LocalContainerEntityManagerFactoryBean em = new 
     LocalContainerEntityManagerFactoryBean();
     em.setDataSource(dataSource());
     em.setPackagesToScan(new String[] { "model.entities" });

     JpaVendorAdapter vendorAdapter = new HibernateJpaVendorAdapter();
     em.setJpaVendorAdapter(vendorAdapter);
     em.setJpaProperties(additionalProperties());
     return em;
   }

....