Spring Boot 2.x 多数据源配置之 JPA 篇
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：
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
