Spring Boot — Multiple DB Connect using Hibernate | Spring Boot

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In this tutorial we’ll learn how to connect 2 DB using Spring Boot + Hibernate.

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
	<modelVersion>4.0.0</modelVersion>
	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>2.1.6.RELEASE</version>
		<relativePath /> <!-- lookup parent from repository -->
	</parent>
	<groupId>com.example</groupId>
	<artifactId>multiple_db_connect</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<name>multiple_db_connect</name>
	<description>Demo project for Spring Boot</description>
	<properties>
		<java.version>1.8</java.version>
	</properties>
	<dependencies>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
		</dependency>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-test</artifactId>
			<scope>test</scope>
		</dependency>
		<dependency>
			<groupId>org.hibernate</groupId>
			<artifactId>hibernate-core</artifactId>
			<version>5.4.2.Final</version>
		</dependency>
		<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-orm</artifactId>
			<version>5.1.6.RELEASE</version>
		</dependency>
		<dependency>
			<groupId>mysql</groupId>
			<artifactId>mysql-connector-java</artifactId>
		</dependency>
	</dependencies>
	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
			</plugin>
		</plugins>
	</build>
</project>

application.properties

hibernate.dialect = org.hibernate.dialect.MySQL5InnoDBDialect
hibernate.show_sql = true
hibernate.format_sql = true
hibernate.hbm2ddl.auto = update
jdbc.test1.driverClassName = com.mysql.jdbc.Driver
jdbc.test1.url = jdbc:mysql://localhost:3306/DATABASE1?useSSL=false
jdbc.test1.username = USERNAME1
jdbc.test1.password = PASSWORD1
jdbc.test2.driverClassName = com.mysql.jdbc.Driver
jdbc.test2.url = jdbc:mysql://localhost:3306/DATABASE2?useSSL=false
jdbc.test2.username = USERNAME2
jdbc.test2.password = PASSWORD2

MultipleDbConnectApplication.java

package com.example;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
public class MultipleDbConnectApplication {
	public static void main(String[] args) {
		SpringApplication.run(MultipleDbConnectApplication.class, args);
		System.out.println("DONE");
	}
}

DBConfiguration.java

package com.example.configure;
import java.util.Properties;
import javax.sql.DataSource;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframework.core.env.Environment;
import org.springframework.jdbc.datasource.DriverManagerDataSource;
import org.springframework.orm.hibernate5.HibernateTransactionManager;
import org.springframework.orm.hibernate5.LocalSessionFactoryBean;
import org.springframework.transaction.annotation.EnableTransactionManagement;
@Configuration
@EnableTransactionManagement
public class DBConfiguration {
	@Autowired
    private Environment environment;
	
	@Bean(name = "test1")
	@Primary
	public LocalSessionFactoryBean test1SessionFactory() {
		LocalSessionFactoryBean sessionFactory = new LocalSessionFactoryBean();
		sessionFactory.setDataSource(test1DataSource());
		sessionFactory.setPackagesToScan("com.example");
		sessionFactory.setHibernateProperties(hibernateProperties());
		return sessionFactory;
	}
	@Bean
	public DataSource test1DataSource() {
		DriverManagerDataSource dataSource = new DriverManagerDataSource();
		dataSource.setDriverClassName(environment.getProperty("jdbc.test1.driverClassName"));
		dataSource.setUrl(environment.getProperty("jdbc.test1.url"));
		dataSource.setUsername(environment.getProperty("jdbc.test1.username"));
		dataSource.setPassword(environment.getProperty("jdbc.test1.password"));
		return dataSource;
	}
	@Bean
    public HibernateTransactionManager getTransactionManagerTest1() {
        HibernateTransactionManager transactionManager = new HibernateTransactionManager();
        transactionManager.setSessionFactory(test1SessionFactory().getObject());
        return transactionManager;
    }
	
	@Bean(name = "test2")
	public LocalSessionFactoryBean test2SessionFactory() {
		LocalSessionFactoryBean sessionFactory = new LocalSessionFactoryBean();
		sessionFactory.setDataSource(test2DataSource());
		sessionFactory.setPackagesToScan("com.example");
		sessionFactory.setHibernateProperties(hibernateProperties());
		return sessionFactory;
	}
	@Bean
	public DataSource test2DataSource() {
		DriverManagerDataSource dataSource = new DriverManagerDataSource();
		dataSource.setDriverClassName(environment.getProperty("jdbc.test2.driverClassName"));
		dataSource.setUrl(environment.getProperty("jdbc.test2.url"));
		dataSource.setUsername(environment.getProperty("jdbc.test2.username"));
		dataSource.setPassword(environment.getProperty("jdbc.test2.password"));
		return dataSource;
	}
	@Bean
    public HibernateTransactionManager getTransactionManagerTest2() {
        HibernateTransactionManager transactionManager = new HibernateTransactionManager();
        transactionManager.setSessionFactory(test2SessionFactory().getObject());
        return transactionManager;
    }
	
	private Properties hibernateProperties() {
        Properties properties = new Properties();
        properties.put("hibernate.dialect", environment.getRequiredProperty("hibernate.dialect"));
        properties.put("hibernate.show_sql", environment.getRequiredProperty("hibernate.show_sql"));
        properties.put("hibernate.format_sql", environment.getRequiredProperty("hibernate.format_sql"));
        properties.put("hibernate.hbm2ddl.auto", environment.getRequiredProperty("hibernate.hbm2ddl.auto"));
        return properties;
    }
}

ConnectionDemo.java

package com.example.controller;
import java.util.Date;
import org.hibernate.SessionFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;
@RestController
public class ConnectionDemo {
	@Autowired
	@Qualifier("test1")
	SessionFactory db1;
	
	@Autowired
	@Qualifier("test2")
	SessionFactory db2;
	
	@GetMapping("/hello")
	@ResponseBody
	public String hello() {
		System.out.println("db1 : " + db1);
		System.out.println("db2 : " + db2);
		System.out.println(new Date());
		return "hello";
	}
}

Output in console:

db1 : org.hibernate.internal.SessionFactoryImpl@768ad1d6
db2 : org.hibernate.internal.SessionFactoryImpl@9740b6c