【Spring Boot (JPA編)】複数のDBに接続する設定

• Spring Boot + JPA で複数 DB に同時接続する方法
• main クラスに @SpringBootApplication と @EnableJpaRepositories を付与
• DataSource / EntityManager / TransactionManager を DB 毎に Bean 定義
• Repository インターフェースは パッケージで分離し、@EnableJpaRepositories(basePackages = ...) で振り分け

@SpringBootApplication

@EnableJpaRepositories

public class SampleApplication {

    public static void main(String[] args) {

        SpringApplication.run(SampleApplication.class, args);

    }

}

spring.datasource.db1.driverClassName= ...
spring.datasource.db1.url= ...
spring.datasource.db1.username= ...
spring.datasource.db1.password= ...

spring.datasource.db2.driverClassName= ...
spring.datasource.db2.url= ...
spring.datasource.db2.username= ...
spring.datasource.db2.password= ...

package ....entity.db1;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Table;

import lombok.Getter;
import lombok.Setter;

@Getter
@Setter
@Entity
@Table(name="TABLE1")
public class Table1 {

    @Column
    private String col1;
    
    ...
}

package ....repository.db1;

import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;

import ....entity.db1.Test1;

@Repository
public interface Table1RepositoryDb1 extends JpaRepository{
}
 

package ....db;

import javax.sql.DataSource;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.autoconfigure.jdbc.DataSourceProperties;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.boot.orm.jpa.EntityManagerFactoryBuilder;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;
import org.springframework.orm.jpa.JpaTransactionManager;
import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;

@Configuration
@EnableJpaRepositories(
        basePackages = "...repository.db1",
        entityManagerFactoryRef = "db1EntityManager",
        transactionManagerRef = "db1TransactionManager"
)

public class Db1DataSourceConfiguration {

    @Bean
    @Primary
    @ConfigurationProperties(prefix = "spring.datasource.db1")
    public DataSourceProperties db1Properties() {
        return new DataSourceProperties();
    }

    @Bean
    @Primary
    @Autowired
    public DataSource db1DataSource(@Qualifier("db1Properties")
            DataSourceProperties properties) {
        return properties.initializeDataSourceBuilder().build();
    }

    @Bean
    @Primary
    @Autowired
    public LocalContainerEntityManagerFactoryBean db1EntityManager(EntityManagerFactoryBuilder builder,@Qualifier("db1DataSource") DataSource dataSource){
        return builder.dataSource(dataSource)
                .packages("....entity.db1")
                .persistenceUnit("db1")
                .build();
    }
    
    @Bean
    @Primary
    @Autowired
    public JpaTransactionManager db1TransactionManager(@Qualifier("db1EntityManager") LocalContainerEntityManagerFactoryBean db1EntityManager) {
        JpaTransactionManager transactionManager = new JpaTransactionManager();
        transactionManager.setEntityManagerFactory(db1EntityManager.getObject());
        return transactionManager;
    }
}