Spring 4 DB Config - Spring Data JPA and Hibernate - Multiple DBs - Separate Datasources/TransactionManagers/EntityManagers/

Spring4MultipleDBsConfig.java

@Configuration
@EnableTransactionManagement
@PropertySource("classpath:my/db.properties")
@EnableJpaRepositories(
        entityManagerFactoryRef = "DB1EntityManagerFactory",
        transactionManagerRef = "DB1TransactionManager",
        basePackages = "package.to.db1.dao")
public class DB1Config {

    @Autowired private Environment env;

    @Bean(name = "DB1datasource")
    public DataSource dataSource() {
        BasicDataSource dataSource = new BasicDataSource();
        dataSource.setDriverClassName(env.getProperty("my.driver.clazz.name"));
        dataSource.setUrl("myJDBCUrl");
        return dataSource;

    }

    @Bean(name = "DB1datasourceProxyListeners")
    public ChainListener datasourceProxyListeners() {
        ChainListener chainListener = new ChainListener();
            List<QueryExecutionListener> listeners = new ArrayList<>();
                SLF4JQueryLoggingListener slf4jListener = new SLF4JQueryLoggingListener();
                slf4jListener.setLogLevel(SLF4JLogLevel.valueOf(env.getProperty("the.loglevel")));
            listeners.add(slf4jListener);
            listeners.add(new DataSourceQueryCountListener());
        chainListener.setListeners(listeners);
        return chainListener;
    }

    @Bean(name = "DB1datasourceProxy")
    public DataSource dataSourceProxy() {
        ProxyDataSource proxyDataSource = new ProxyDataSource();
            proxyDataSource.setDataSource(dataSource());
            proxyDataSource.setListener(datasourceProxyListeners());
        return proxyDataSource;
    }

    @Bean(name = "DB1JpaVendorAdapter")
    public JpaVendorAdapter jpaVendorAdapter(){
        HibernateJpaVendorAdapter hibernateJpaVendorAdapter = new HibernateJpaVendorAdapter();
        //If proxy datasource then we don't need
        hibernateJpaVendorAdapter.setShowSql(false);
        hibernateJpaVendorAdapter.setDatabasePlatform("org.hibernate.dialect.SQLServer2012Dialect");
        return hibernateJpaVendorAdapter;
    }

    @Bean(name = "DB1EntityManagerFactory")
    public EntityManagerFactory entityManagerFactory() {
        LocalContainerEntityManagerFactoryBean lef = new LocalContainerEntityManagerFactoryBean();
            //datasource or proxy datasource
            lef.setDataSource(dataSourceProxy());
            lef.setJpaVendorAdapter(jpaVendorAdapter());
            lef.setPackagesToScan("package.to.db1.dao.entity");
            lef.setPersistenceUnitName("DB1PersistenceUnit");
            lef.afterPropertiesSet();
        return lef.getObject();
    }

    @Bean(name = "DB1EntityManager")
    public EntityManager entityManager(){
        return entityManagerFactory().createEntityManager();
    }

    @Bean(name = "DB1TransactionManager")
    public PlatformTransactionManager transactionManager() {
            return new JpaTransactionManager((entityManagerFactory()));
    }
}