spring.primary.url=jdbc:postgresql://localhost:5432/kode12
spring.primary.username=postgres
spring.primary.password=root
spring.primary.driverClassName=org.postgresql.Driver

spring.secondary.url=jdbc:mysql://localhost:3306/kode12
spring.secondary.username=root
spring.secondary.password=root
spring.secondary.driverClassName=com.mysql.jdbc.Driver

package com.test;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public Application {
    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
}

package com.test.config;
import javax.sql.DataSource;
import org.springframework.boot.autoconfigure.jdbc.DataSourceBuilder;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;

@Configuration
public class ApplicationConfiguration {

    @Primary
    @Bean(name = "primaryDB")
    @ConfigurationProperties(prefix = "spring.primary")
    public DataSource postgresDataSource() {
        return  DataSourceBuilder.create().build();
    }

    @Bean(name = "primaryEM")
    public LocalContainerEntityManagerFactoryBean storingEntityManagerFactory(
        EntityManagerFactoryBuilder builder, @Qualifier("primaryDB") DataSource ds) {
        return builder
            .dataSource(ds)
            .packages("com.test")
            .persistenceUnit("primaryPU")
            .build();
    }

    @Bean(name = "secondaryDB")
    @ConfigurationProperties(prefix = "spring.secondary")
    public DataSource mysqlDataSource() {
        return DataSourceBuilder.create().build();
    }

    @Bean(name = "secondaryEM")
    public LocalContainerEntityManagerFactoryBean storingEntityManagerFactory(
        EntityManagerFactoryBuilder builder, @Qualifier("secondaryDB") DataSource ds) {
    return builder
            .dataSource(ds)
            .packages("com.test")
            .persistenceUnit("secondaryPU")
            .build();
    }

}

public abstract class GenericDAO<T extends Serializable> {

    private Class<T> clazz = null;

    @PersistenceContext
    protected EntityManager entityManager;

    public void setClazz(Class<T> clazzToSet) {
        this.clazz = clazzToSet;
    }

    public T findOne(Integer id) {
        return this.entityManager.find(this.clazz, id);
    }

    public List<T> findAll() {
        return this.entityManager.createQuery("from " + this.clazz.getName()).getResultList();
    }

    @Transactional
    public void save(T entity) {
        this.entityManager.persist(setModifiedAt(entity));
    }
}

@Repository
public class PersonDAO extends GenericDAO<Person> {
    public PersonDAO() {
        this.setClazz(Person.class);
    }
}

@Repository
public class ProductDAO extends GenericDAO<Product> {
    public ProductDAO() {
        this.setClazz(Product.class);
    }
}

@Service
public class TestService {

    @Autowired
    @PersistenceContext(name = "primaryEm")
    PersonDAO personDao;

    @Autowired
    @PersistenceContext(name = "secondaryEm")
    ProductDAO productDao;

    // This should write to primary datasource
    public void savePerson(Person person) {
        personDao.save(person);
    }

    // This should write to secondary datasource
    public void saveProduct(Product product) {
        productDao.save(product);
    }

}