Spring Boot で複数のデータ ソースを構成して使用する方法は?

# First Data Source
spring.datasource.url=[URL]
spring.datasource.username=[USERNAME]
spring.datasource.password=[PASSWORD]
spring.datasource.driverClassName=oracle.jdbc.OracleDriver

# Second Data Source
spring.secondDatasource.url=[URL]
spring.secondDatasource.username=[USERNAME]
spring.secondDatasource.password=[PASSWORD]
spring.secondDatasource.driverClassName=oracle.jdbc.OracleDriver

@Bean
@Primary
@ConfigurationProperties(prefix="spring.datasource")
public DataSource primaryDataSource() {
    return DataSourceBuilder.create().build();
}

@Bean
@ConfigurationProperties(prefix="spring.secondDatasource")
public DataSource secondaryDataSource() {
    return DataSourceBuilder.create().build();
}

@Repository
public class UserRepository {
    @Autowired
    private EntityManager entityManager;
    // ...
}

@Repository
public class OrderRepository {
    @Autowired
    @Qualifier("secondaryDataSource")
    private EntityManager entityManager;
    // ...
}