I've created a working example for you, I'll describe it here but if you want to jump in the code yourself it's available at this GitHub repo.
In my case, I've created two data sources, one for User and another one for Item.
Here the entities:
package com.marcosbarbero.so.multiple.ds.entity.user;
import lombok.Data;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;
@Data
@Entity
@Table(schema = "user")
public class User {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private Integer id;
private String name;
@Column(unique = true, nullable = false)
private String email;
private int age;
}
package com.marcosbarbero.so.multiple.ds.entity.item;
import lombok.Data;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;
@Data
@Entity
@Table(schema = "item")
public class Item {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private int id;
private String name;
}
Note, It's important to have distinct packages for each domain.
Then I created the Repositories
package com.marcosbarbero.so.multiple.ds.repository.user;
import com.marcosbarbero.so.multiple.ds.entity.user.User;
import org.springframework.data.jpa.repository.JpaRepository;
public interface UserRepository extends JpaRepository<User, Integer> {
}
package com.marcosbarbero.so.multiple.ds.repository.item;
import com.marcosbarbero.so.multiple.ds.entity.item.Item;
import org.springframework.data.jpa.repository.JpaRepository;
public interface ItemRepository extends JpaRepository<Item, Integer> {
}
Nothing special about the repos. Let's move to the final piece, the configuration.
- I created a
@ConfigurationProperties class to externalize my configuration, bear with me, I know the naming is not the best :)
package com.marcosbarbero.so.multiple.ds.config;
import lombok.Data;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;
import java.util.HashMap;
import java.util.Map;
@Data
@Component
@ConfigurationProperties(prefix = "multi-datasource")
public class MultipleDataSourceProperties {
private UserDataSourceProperties user = new UserDataSourceProperties();
private ItemDataSourceProperties item = new ItemDataSourceProperties();
@Data
public static class UserDataSourceProperties {
private HibernateProperties hibernate = new HibernateProperties();
}
@Data
public static class ItemDataSourceProperties {
private HibernateProperties hibernate = new HibernateProperties();
}
@Data
public static class HibernateProperties {
private Map<String, String> properties = new HashMap<>();
}
}
We'll see the properties configuration file soon.
- Now let's create the
DataSource for the User:
package com.marcosbarbero.so.multiple.ds.config;
import com.zaxxer.hikari.HikariDataSource;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.boot.jdbc.DataSourceBuilder;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;
import org.springframework.orm.jpa.JpaTransactionManager;
import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;
import org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter;
import org.springframework.transaction.PlatformTransactionManager;
import javax.sql.DataSource;
@Configuration
@EnableJpaRepositories(
basePackages = "com.marcosbarbero.so.multiple.ds.repository.user",
entityManagerFactoryRef = "userEntityManager",
transactionManagerRef = "userTransactionManager"
)
public class UserDataSourceConfig {
private final MultipleDataSourceProperties properties;
public UserDataSourceConfig(MultipleDataSourceProperties properties) {
this.properties = properties;
}
@Bean
@Primary
public LocalContainerEntityManagerFactoryBean userEntityManager() {
LocalContainerEntityManagerFactoryBean em = new LocalContainerEntityManagerFactoryBean();
em.setDataSource(userDataSource());
em.setPackagesToScan("com.marcosbarbero.so.multiple.ds.entity.user");
HibernateJpaVendorAdapter vendorAdapter = new HibernateJpaVendorAdapter();
em.setJpaVendorAdapter(vendorAdapter);
em.setJpaPropertyMap(properties.getUser().getHibernate().getProperties());
return em;
}
@Primary
@Bean
@ConfigurationProperties("multi-datasource.user")
public DataSource userDataSource() {
return DataSourceBuilder.create().type(HikariDataSource.class).build();
}
@Primary
@Bean
public PlatformTransactionManager userTransactionManager() {
JpaTransactionManager transactionManager = new JpaTransactionManager();
transactionManager.setEntityManagerFactory(userEntityManager().getObject());
return transactionManager;
}
}
The important part for you at this class is the line em.setJpaPropertyMap(properties.getUser().getHibernate().getProperties()); it's getting the User's Hibernate configuration properties from our @ConfigurationProperties class defined above.
- Now let's do the same for the
Item:
package com.marcosbarbero.so.multiple.ds.config;
import com.zaxxer.hikari.HikariDataSource;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.boot.jdbc.DataSourceBuilder;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;
import org.springframework.orm.jpa.JpaTransactionManager;
import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;
import org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter;
import org.springframework.transaction.PlatformTransactionManager;
import javax.sql.DataSource;
@Configuration
@EnableJpaRepositories(
basePackages = "com.marcosbarbero.so.multiple.ds.repository.item",
entityManagerFactoryRef = "itemEntityManager",
transactionManagerRef = "itemTransactionManager"
)
public class ItemDataSourceConfig {
private final MultipleDataSourceProperties properties;
public ItemDataSourceConfig(MultipleDataSourceProperties properties) {
this.properties = properties;
}
@Bean
@Primary
public LocalContainerEntityManagerFactoryBean itemEntityManager() {
LocalContainerEntityManagerFactoryBean em = new LocalContainerEntityManagerFactoryBean();
em.setDataSource(itemDataSource());
em.setPackagesToScan("com.marcosbarbero.so.multiple.ds.entity.item");
HibernateJpaVendorAdapter vendorAdapter = new HibernateJpaVendorAdapter();
em.setJpaVendorAdapter(vendorAdapter);
em.setJpaPropertyMap(properties.getItem().getHibernate().getProperties());
return em;
}
@Primary
@Bean
@ConfigurationProperties("multi-datasource.item")
public DataSource itemDataSource() {
return DataSourceBuilder.create().type(HikariDataSource.class).build();
}
@Primary
@Bean
public PlatformTransactionManager itemTransactionManager() {
JpaTransactionManager transactionManager = new JpaTransactionManager();
transactionManager.setEntityManagerFactory(itemEntityManager().getObject());
return transactionManager;
}
}
- The
application.properties
multi-datasource.item.jdbcUrl=jdbc:h2:mem:spring_jpa_item;DB_CLOSE_DELAY=-1;INIT=CREATE SCHEMA IF NOT EXISTS ITEM
multi-datasource.item.username=sa
multi-datasource.item.password=sa
multi-datasource.item.hibernate.properties.hibernate.hbm2ddl.auto=create-drop
multi-datasource.item.hibernate.properties.hibernate.cache.use_second_level_cache=false
multi-datasource.item.hibernate.properties.hibernate.cache.use_query_cache=false
multi-datasource.item.hibernate.properties.hibernate.dialect=org.hibernate.dialect.PostgreSQLDialect
multi-datasource.user.jdbcUrl=jdbc:h2:mem:spring_jpa_user;DB_CLOSE_DELAY=-1;INIT=CREATE SCHEMA IF NOT EXISTS USER
multi-datasource.user.username=sa
multi-datasource.user.password=sa
multi-datasource.user.hibernate.properties.hibernate.hbm2ddl.auto=create-drop
multi-datasource.user.hibernate.properties.hibernate.cache.use_second_level_cache=false
multi-datasource.user.hibernate.properties.hibernate.cache.use_query_cache=false
multi-datasource.user.hibernate.properties.hibernate.dialect=org.hibernate.dialect.OracleDialect
- Some unit tests
package com.marcosbarbero.so;
import com.marcosbarbero.so.multiple.ds.entity.item.Item;
import com.marcosbarbero.so.multiple.ds.entity.user.User;
import com.marcosbarbero.so.multiple.ds.repository.item.ItemRepository;
import com.marcosbarbero.so.multiple.ds.repository.user.UserRepository;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import static org.junit.jupiter.api.Assertions.assertNotNull;
@SpringBootTest
public class JPAMultipleDBTest {
@Autowired
private UserRepository userRepository;
@Autowired
private ItemRepository itemRepository;
@Test
public void whenCreatingUser_thenCreated() {
User user = new User();
user.setName("John");
user.setEmail("john@test.com");
user.setAge(20);
user = userRepository.save(user);
assertNotNull(userRepository.findById(user.getId()));
}
@Test
public void whenCreatingProduct_thenCreated() {
Item item = new Item();
item.setName("Book");
item.setId(2);
item = itemRepository.save(item);
assertNotNull(itemRepository.findById(item.getId()));
}
}
I think it also worth mentioning, to make it all work I disabled the DataSourceAutoConfiguration, it's simple as that:
@SpringBootApplication(exclude = DataSourceAutoConfiguration.class)
And again, it all is available at this GitHub repo.