Spring Boot config for multiple datasources and EntityManagerFactories

DataSourceConfig.java

package com.pascaldimassimo.xyz;

import java.util.HashMap;
import java.util.Map;

import javax.persistence.EntityManagerFactory;
import javax.sql.DataSource;

import org.hibernate.cfg.ImprovedNamingStrategy;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.autoconfigure.jdbc.DataSourceBuilder;
import org.springframework.boot.autoconfigure.orm.jpa.EntityManagerFactoryBuilder;
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;
import org.springframework.orm.jpa.JpaTransactionManager;
import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;
import org.springframework.transaction.PlatformTransactionManager;

@Configuration
public class DataSourceConfig {

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

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

    @Bean(name = "entityManagerFactory")
    @Primary
    public LocalContainerEntityManagerFactoryBean prodEntityManagerFactory(
            EntityManagerFactoryBuilder builder) {
        return builder
                .dataSource(prodDataSource())
                .packages("com.pascaldimassimo.xyz")
                .persistenceUnit("prod")
                .properties(buildProperties())
                .build();
    }

    @Bean(name = "secondaryEntityManagerFactory")
    public LocalContainerEntityManagerFactoryBean secondaryEntityManagerFactory(
            EntityManagerFactoryBuilder builder) {
        return builder
                .dataSource(secondaryDataSource())
                .packages("com.pascaldimassimo.xyz")
                .persistenceUnit("secondary")
                .properties(buildProperties())
                .build();
    }
    
    private Map<String, Object> buildProperties() {
        // This is usually set by HibernateJpaAutoConfiguration
        Map<String, Object> properties = new HashMap<String, Object>();
        properties.put("hibernate.ejb.naming_strategy",
                ImprovedNamingStrategy.class.getName());
        return properties;
    }

    @Bean
    @Autowired
    @Qualifier("secondaryEntityManagerFactory")
    public PlatformTransactionManager transactionManager(EntityManagerFactory emf) {
        JpaTransactionManager txManager = new JpaTransactionManager();
        txManager.setEntityManagerFactory(emf);
        return txManager;
    }
}

@pascaldimassimo same question here

@pascaldimassimo same question here