Using Multiple Database in Spring boot - mysql

Question

I encounted a problem when I wanted to work between two database, I wanted to use the table 1 in database 1 and the table 2 in database 2, I tried so many ways, but all seems not work.
spring.datasource.primary.url = jdbc:mysql://localhost:3306/mydb?useUnicode=true&characterEncoding=UTF-8
spring.datasource.primary.username = root
spring.datasource.primary.password = xxxx
spring.datasource.primary.driverClassName=com.mysql.jdbc.Driver
spring.datasource.secondary.url = jdbc:mysql://localhost:3306/testdb?useUnicode=true&characterEncoding=UTF-8
spring.datasource.secondary.username = root
spring.datasource.secondary.password = xxxx
spring.datasource.secondary.driverClassName=com.mysql.jdbc.Driver
above is my application.properties. Then I used #Primary setting spring.datasource.primary as the primary database in config file.
#Entity
#Table(name = "User")
public class User {
#Id
#NotNull
#Column(name = "phoneid")
private String phoneid;
}
public interface UserDAO extends CrudRepository<User, String> {
public User findByPhoneid(String phoneid);
}
I want to connect to database spring.datasource.primary and use the table User in it.
#Entity
#Table(name = "Favorite_Restaurant")
public class FavoriteRestaurant {
#Id
#NotNull
#Column(name = "favorite_restaurantid")
private int favoriteRestaurantId;
}
public interface FavoriteRestaurantDAO extends JpaRepository<FavoriteRestaurant, Integer> {
public List<FavoriteRestaurant> findAll(Sort sort);
}
I want to connect to database spring.datasource.secondary and use the table FavoriteRestaurant in it.
However when I Autowired UserDAo and FavoriteRestaurantDAO in My Service, It seems just like it autowired both userdao and favoriterestaurantdao from primary database. How can I inject FavoriteRestaurantDAO from secondary database!!!!! help!!!!!!

Answer 1

To be able to use several datasources you need to have several persistent unit configurations.
I will assume that you've got datasourceA and datasourceB to configure.
We have one configuration class for each of our persistent units. The listing contains the class for datasourceA (you will have to copy and adjust the configuration for datasourceB).
It's also a good idea not to mix the entities from different persistent units.
So we have separated them based on the package. We have created an empty class
SpringRootPackageMarker so that it tells spring which packages to scan.
Note! the SpringRootPackageMarker class is used in both #EnableJpaRepositories and in getDatasourceAEntityManagerFactoryBean method
So this is our way how to do it:
#DependsOn("transactionManager")
#EnableJpaRepositories(
basePackageClasses = SpringRootPackageMarker.class,
entityManagerFactoryRef = "datasourceAEntityManager",
transactionManagerRef = "transactionManager")
public class DatasourceAPersistenceUnitConfiguration {
private static final String DATASOURCE_A_PERSISTENT_UNIT_NAME = "datasourceAPU";
#DependsOn("transactionManager") // for unit tests
#Bean(name = "datasourceAEntityManager")
public LocalContainerEntityManagerFactoryBean getDatasourceAEntityManagerFactoryBean() {
final LocalContainerEntityManagerFactoryBean factory = new LocalContainerEntityManagerFactoryBean();
factory.setPersistenceUnitName(DATASOURCE_A_PERSISTENT_UNIT_NAME);
factory.setDataSource(getDatasourceA());
factory.setJpaVendorAdapter(getDatasourceAJpaVendorAdapter());
factory.setPackagesToScan(SpringRootPackageMarker.class.getPackage().getName());
Properties jpaProperties = getDatasourceAJpaProperties();
factory.setJpaProperties(jpaProperties);
return factory;
}
#Bean
public DataSource getDatasourceA() {
DataSource datasource = null;
// prepare datasource A;
return datasource;
}
private JpaVendorAdapter getDatasourceAJpaVendorAdapter() {
final HibernateJpaVendorAdapter vendorAdapter = new HibernateJpaVendorAdapter();
//custom configuration for datasource A
return vendorAdapter;
}
private Properties getDatasourceAJpaProperties() {
Properties jpaProperties = new Properties();
//custom properties
return jpaProperties;
}
}
}
if you plan to inject the entityManager into your application you'll have to do it this way:
#PersistenceContext(unitName= DatasourceAPersistenceUnitConfiguration.DATASOURCE_A_PERSISTENT_UNIT_NAME)
private EntityManager manager;

Answer 2

Finally, I solved this problem by adding #EnableAutoConfiguration above my config class
#Configuration
#EnableJpaRepositories(basePackages = "datamodel.dao", entityManagerFactoryRef = "localEntityManagerFactory", transactionManagerRef = "localTransactionManager")
#EnableTransactionManagement
#EnableAutoConfiguration ///the key to make spring boot know your config!!!!!!!!!!!!!
public class MainDataConfig {
#Bean
#ConfigurationProperties(prefix = "datasource.main")
#Primary
public DataSource localDataSource() {
return DataSourceBuilder.create().build();
}
#Bean
#Primary
public LocalContainerEntityManagerFactoryBean localEntityManagerFactory(final EntityManagerFactoryBuilder builder) {
return builder.dataSource(localDataSource()).packages("datamodel.domain")
.persistenceUnit("mainPersistenceUnit").build();
}
#Bean
#Primary
public JpaTransactionManager localTransactionManager(#Qualifier("localEntityManagerFactory") final EntityManagerFactory factory) {
return new JpaTransactionManager(factory);
}
}