场景假设：现有电商业务，商品和库存分别放在不同的库
配置数据库连接 app: datasource: first: driver-class-name: com.mysql.cj.jdbc.Driver url: jdbc:mysql://127.0.0.1/product?useSSL=false username: root password: root configuration: maximum-pool-size: 10 second: driver-class-name: com.mysql.cj.jdbc.Driver url: jdbc:mysql://127.0.0.1/stock?useSSL=false username: root password: root configuration: maximum-pool-size: 10 添加配置类 FirstConfig @Configuration @EnableJpaRepositories( basePackages = {"com.karonda.springboot2datasourcesjpa.dao.first"},// 1. dao 层所在的包 entityManagerFactoryRef = "firstEntityManagerFactory", transactionManagerRef = "firstTransactionManager") @EnableTransactionManagement public class FirstConfig { @Bean @Primary public PlatformTransactionManager firstTransactionManager() { return new JpaTransactionManager(firstEntityManagerFactory().getObject()); } @Bean @Primary public LocalContainerEntityManagerFactoryBean firstEntityManagerFactory() { HibernateJpaVendorAdapter jpaVendorAdapter = new HibernateJpaVendorAdapter(); LocalContainerEntityManagerFactoryBean factoryBean = new LocalContainerEntityManagerFactoryBean(); factoryBean.setDataSource(firstDataSource()); factoryBean.setJpaVendorAdapter(jpaVendorAdapter); factoryBean.setJpaProperties(hibernateProperties()); factoryBean.setPackagesToScan("com.karonda.springboot2datasourcesjpa.entity.first");// 2. 实体类所在的包 return factoryBean; } @Bean @Primary @ConfigurationProperties("app.datasource.first") public DataSourceProperties firstDataSourceProperties() { return new DataSourceProperties(); } @Bean @Primary @ConfigurationProperties("app.datasource.first.configuration") public DataSource firstDataSource() { return firstDataSourceProperties() .initializeDataSourceBuilder() .type(HikariDataSource.class) // 3. 可以显示指定连接池，也可以不显示指定；即此行代码可以注释掉 .build(); } private Properties hibernateProperties() { final Properties hibernateProperties = new Properties(); hibernateProperties.setProperty("hibernate.dialect", "org.hibernate.dialect.MySQL5Dialect"); // hibernateProperties.setProperty("hibernate.hbm2ddl.auto", "create"); return hibernateProperties; } } SecondConfig @Configuration @EnableJpaRepositories( basePackages = {"com.karonda.springboot2datasourcesjpa.dao.second"}, entityManagerFactoryRef = "secondEntityManagerFactory", transactionManagerRef = "secondTransactionManager") @EnableTransactionManagement public class SecondConfig { @Bean public PlatformTransactionManager secondTransactionManager() { return new JpaTransactionManager(secondEntityManagerFactory().getObject()); } @Bean public LocalContainerEntityManagerFactoryBean secondEntityManagerFactory() { HibernateJpaVendorAdapter jpaVendorAdapter = new HibernateJpaVendorAdapter(); LocalContainerEntityManagerFactoryBean factoryBean = new LocalContainerEntityManagerFactoryBean(); factoryBean.setDataSource(secondDataSource()); factoryBean.setJpaVendorAdapter(jpaVendorAdapter); factoryBean.setJpaProperties(hibernateProperties()); factoryBean.setPackagesToScan("com.karonda.springboot2datasourcesjpa.entity.second"); return factoryBean; } @Bean @ConfigurationProperties("app.datasource.second") public DataSourceProperties secondDataSourceProperties() { return new DataSourceProperties(); } @Bean @ConfigurationProperties("app.datasource.second.configuration") public DataSource secondDataSource() { return secondDataSourceProperties() .initializeDataSourceBuilder() .type(HikariDataSource.class) .build(); } private Properties hibernateProperties() { final Properties hibernateProperties = new Properties(); hibernateProperties.setProperty("hibernate.dialect", "org.hibernate.dialect.MySQL5Dialect"); // hibernateProperties.setProperty("hibernate.hbm2ddl.auto", "create"); return hibernateProperties; } } dao public interface ProductDao extends JpaRepository<Product, Integer> { @Query(value = "select p from Product p where p.id = id") Product findById(@Param("id") int id); } public interface StockDao extends JpaRepository<Stock, Integer> { @Query(value = "select s from Stock s where s.productId = productId") Stock findByProductId(@Param("productId") int productId); } 使用示例 @Component public class Task { @Autowired private ProductDao productDao; @Autowired private StockDao stockDao; @Scheduled(cron = "0/5 * * * * ? ") public void job(){ final int productId = 1; Product product = productDao.findById(productId); Stock stock = stockDao.findByProductId(productId); System.out.println("产品名称: " + product.getName() + ", 库存: " + stock.getStockCount()); } } 注意事项使用多数据源，其中一个配置类需要添加 @Primary 注解 (有且仅有一个配置类需要添加)
在配置类中需要同时配置 dao 层和实体类所在的包
参考：
spring+Jpa多数据源配置的方法示例
完整代码：GitHub
本人 C# 转 Java 的 newbie, 如有错误或不足欢迎指正，谢谢