java - Hibernate 连接到具有相同表的多个数据库

Question

我必须连接到包含相同表的两个数据库(PostgreSQL、Oracle)。当我在不同的包中创建相同表的实体时，它不起作用。

即使使用两个数据库连接，应用程序始终只指向一个数据库连接。

在 Hibernate 中是否可以连接到来自不同数据库的相同表？

application.properties

#DataSource settings for Postgres
datasource.secondary.url =jdbc:postgresql://localhost:5433/****
datasource.secondary.username =postgres
datasource.secondary.password =Postgre@1234
datasource.secondary.driverClassName=org.postgresql.Driver
datasource.secondary.dialect=org.hibernate.dialect.PostgreSQLDialect

#DataSource settings for oracle
datasource.primary.url = jdbc:oracle:thin:@localhost:1521:xe
datasource.primary.username = ***
datasource.primary.password = ***
datasource.primary.driverClassName=oracle.jdbc.OracleDriver

配置

@Configuration
public class MultipleDBConfig {

    @Primary
    @Bean(name = "oracleDb")
    @ConfigurationProperties(prefix = "datasource.primary")
    public DataSource mysqlDataSource() {
        return DataSourceBuilder.create().build();
    }


    @Bean(name = "postgresDb")
    @ConfigurationProperties(prefix = "datasource.secondary")
    public DataSource postgresDataSource() {
        return  DataSourceBuilder.create().build();
    }

}

主要

@Configuration
@EnableJpaRepositories(
            entityManagerFactoryRef = "primaryEntityManager",
            transactionManagerRef = "primaryEntityManagerFactory",
            basePackages = {"com.ubl.model.*"})
public class PrimaryDBConfig {

    @Bean(name = "primaryEntityManagerFactory")
    public LocalContainerEntityManagerFactoryBean entityManagerFactory(){
        JpaVendorAdapter vendorAdapter = new HibernateJpaVendorAdapter();
        LocalContainerEntityManagerFactoryBean em = new LocalContainerEntityManagerFactoryBean();
        em.setDataSource(dataSource());
        em.setPackagesToScan(new String[] {"com.ubl.model.migration.entity.oracle"});
        em.setJpaVendorAdapter(vendorAdapter);
        em.setJpaProperties(additionalJpaProperties());
        em.setPersistenceUnitName("customers");

        return em;
    }

    Properties additionalJpaProperties(){
        Properties properties = new Properties();
        properties.setProperty("hibernate.hbm2ddl.auto", "update");
        properties.setProperty("hibernate.dialect", "org.hibernate.dialect.OracleDialect");
        properties.setProperty("hibernate.show_sql", "true");

        return properties;
    }

    @Bean
    public DataSource dataSource(){
        return DataSourceBuilder.create()
                .url("jdbc:oracle:thin:@localhost:1521:xe")
                .driverClassName("oracle.jdbc.OracleDriver")
                .username("****")
                .password("****")
                .build();
    }   

    @Bean(name = "primarytransactionManager")
    public JpaTransactionManager transactionManager(EntityManagerFactory customerEntityManager){
        JpaTransactionManager transactionManager = new JpaTransactionManager();
        transactionManager.setEntityManagerFactory(customerEntityManager);

        return transactionManager;
    }

}

中学

@Configuration
@EnableTransactionManagement
@EnableJpaRepositories(
        entityManagerFactoryRef = "secondaryEntityManagerFactory",
        transactionManagerRef = "secondaryTransactionManager",
        basePackages = {"com.ubl.*"})
public class SecondaryDBConfig {

    @Autowired
    JpaVendorAdapter jpaVendorAdapter;

    @Value("${datasource.secondary.url}")
    private String databaseURL; 

    @Value("${datasource.secondary.username}")
    private String username;

    @Value("${datasource.secondary.password}")
    private String password;

    @Value("${datasource.secondary.driverClassName}")
    private String driverClassName;

    @Value("${datasource.secondary.dialect}")
    private String dialect;

    public SecondaryDBConfig() {
        System.out.println("Secondary repository");
        System.out.println("driverClassName: *************" +driverClassName);
    }

    public DataSource dataSource() {
        DriverManagerDataSource dataSource = new DriverManagerDataSource(databaseURL, username, password);
        dataSource.setDriverClassName(driverClassName);
        return dataSource;
    }

    @Bean(name = "secondaryEntityManager")
    public EntityManager entityManager() {
        return entityManagerFactory().createEntityManager();
    }

    @Bean(name = "secondaryEntityManagerFactory")
    public EntityManagerFactory entityManagerFactory() {
        Properties properties = new Properties();
        properties.setProperty("hibernate.dialect", dialect);

        LocalContainerEntityManagerFactoryBean emf = new LocalContainerEntityManagerFactoryBean();
        emf.setDataSource(dataSource());
        emf.setJpaVendorAdapter(jpaVendorAdapter);
        emf.setPackagesToScan("com.ubl.model.*");   // package for entities
        emf.setPersistenceUnitName("secondaryPersistenceUnit");
        emf.setJpaProperties(properties);
        emf.afterPropertiesSet();
        return emf.getObject();
    }

    @Bean(name = "secondaryTransactionManager")
    public PlatformTransactionManager transactionManager() {
        return new JpaTransactionManager(entityManagerFactory());
    }


}

当我运行应用程序时，出现以下错误:Caused by: org.hibernate.tool.schema.extract.spi.SchemaExtractionException: 在命名空间 (, ) 中找到多个表

Answer 1

您的第二个配置似乎使用与第一个配置相同的命名空间:

basePackages = {"com.ubl.model.*"}
basePackages = {"com.ubl.*"}

一旦您的第二个配置查找它的实体，它就会发现与第一个配置相同的实体，从而导致异常。您将希望将您的实体和您的配置分开。

basePackages = {"com.ubl.model.datasource1"}
basePackages = {"com.ubl.model.datasource2"} // well you get the idea and will find better names ;)

然后将所有实体移动到相应的文件夹中。虽然表是“相同的”，但每个单独的表都需要一个@Entity-Class，即使您要使用的表在结构上是相同的。