Spring Boot connect Mysql and MongoDb

Question

I have a problem with Spring Boot application. I want to connect a MongoDB database and a MySql database in my Spring boot application. I would to know if it is possible, in positive case How I can make this multiple connection. I had made a try based on an example with Mysql and Post without success. So I'm wondering if someone have an easy example to know the method. thanks

Answer 1

It is possible to do this.you will have create different configuration for different datasources. This link has good examples on that http://www.baeldung.com/spring-data-jpa-multiple-databases

Another useful stackoverflow question: Spring Boot Configure and Use Two DataSources

To get started with mongo and mysql , you can follow example from spring.io guides.

https://spring.io/guides/gs/accessing-data-mongodb/

https://spring.io/guides/gs/accessing-data-mysql/

EDIT :

I have created this one example, merging two samples above

package hello;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;
import org.springframework.data.mongodb.repository.config.EnableMongoRepositories;

import hello.model.Customer;
import hello.model.User;
import hello.mongodao.CustomerRepository;
import hello.mysqldao.UserRepository;

@EnableMongoRepositories(basePackageClasses = CustomerRepository.class)
@EnableJpaRepositories (basePackageClasses = UserRepository.class)
@SpringBootApplication
public class Application implements CommandLineRunner {

    @Autowired
    private CustomerRepository repository;

    @Autowired
    private UserRepository userRepository;

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

        System.out.println("getting data from Mongo");
        repository.deleteAll();

        // save a couple of customers
        repository.save(new Customer("Alice", "Smith"));
        repository.save(new Customer("Bob", "Smith"));

        // fetch all customers
        System.out.println("Customers found with findAll():");
        System.out.println("-------------------------------");
        for (Customer customer : repository.findAll()) {
            System.out.println(customer);
        }
        System.out.println();

        // fetch an individual customer
        System.out.println("Customer found with findByFirstName('Alice'):");
        System.out.println("--------------------------------");
        System.out.println(repository.findByFirstName("Alice"));

        System.out.println("Customers found with findByLastName('Smith'):");
        System.out.println("--------------------------------");
        for (Customer customer : repository.findByLastName("Smith")) {
            System.out.println(customer);
        }

        System.out.println("gettting data from mysql");
        userRepository.deleteAll();

        // save a couple of customers
        userRepository.save(new User("Alice", "Alice@Smith.com"));
        userRepository.save(new User("Bob", "Bob@Smith.com"));

        // fetch all customers
        System.out.println("Users found with findAll():");
        System.out.println("-------------------------------");

        for (User user : userRepository.findAll()) {
            System.out.println(user);
        }

    }
}

CustomerRepository.java

package hello.mongodao;

import java.util.List;

import org.springframework.data.mongodb.repository.MongoRepository;

import hello.model.Customer;

public interface CustomerRepository extends MongoRepository<Customer, String> {

    public Customer findByFirstName(String firstName);
    public List<Customer> findByLastName(String lastName);

}

UserRepository.java

package hello.mysqldao;

import org.springframework.data.repository.CrudRepository;

import hello.model.User;

// This will be AUTO IMPLEMENTED by Spring into a Bean called userRepository
// CRUD refers Create, Read, Update, Delete

public interface UserRepository extends CrudRepository<User, Long> {

}

Customer.java

package hello.model;

import org.springframework.data.annotation.Id;


public class Customer {

    @Id
    public String id;

    public String firstName;
    public String lastName;

    public Customer() {}

    public Customer(String firstName, String lastName) {
        this.firstName = firstName;
        this.lastName = lastName;
    }

    @Override
    public String toString() {
        return String.format(
                "Customer[id=%s, firstName='%s', lastName='%s']",
                id, firstName, lastName);
    }

}

User.java

package hello.model;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;

@Entity // This tells Hibernate to make a table out of this class
public class User {
    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    private Integer id;

    private String name;

    private String email;
public User() {
    // TODO Auto-generated constructor stub
}
    public User(String string, String string2) {
        // TODO Auto-generated constructor stub
        name = string;
        email = string2;
    }

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    @Override
    public String toString() {
        return String.format(
                "User[id=%s, name='%s', email='%s']",
                id, name, email);
    }


}

application.properties

spring.jpa.hibernate.ddl-auto=create
spring.datasource.url=jdbc:mysql://localhost:3306/db_example
spring.datasource.username=springuser
spring.datasource.password=ThePassword
spring.data.mongodb.uri=mongodb://localhost:27017/local

Answer 2

You really don't need to make additional config and property files because MongoDB has different property names than sql so all you will need is an application.properties file

application.properties

spring.datasource.url=jdbc:mysql://${MYSQL_HOST:localhost}:3306/dbName?useUnicode=yes&characterEncoding=UTF-8
spring.datasource.username=root
spring.datasource.password=

spring.data.mongodb.uri=mongodb://localhost:27017
spring.data.mongodb.database=dbName

example models

MongoDB document

import org.springframework.data.mongodb.core.mapping.Document;
import javax.persistence.Id;

    @Document("Gyros")
    public class Gyros {
    
        public Gyros(String description) {
            this.description = description;
        }
    
        @Id
        public String id;
    
        public String description;
    }

Mysql JPA entity

import javax.persistence.*;

@Entity
@Table(name = "Kebab")
public class Kebab {

    public Kebab(String description) {
        this.description = description;
    }

    public Kebab() {
    }

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    public int id;

    public String description;
}

MongoDB repository

@Repository
public interface GyrosRepository extends MongoRepository<Gyros, String> {
}

Mysql Jpa repository

    @Repository
    public interface KebabRepository extends JpaRepository<Kebab, Integer> {
    }

TestService

@org.springframework.stereotype.Service
public class Service {

    private final GyrosRepository gyrosRepository;
    private final KebabRepository kebabRepository;

    @Autowired
    public Service(GyrosRepository gyrosRepository, KebabRepository kebabRepository) {
        this.gyrosRepository = gyrosRepository;
        this.kebabRepository = kebabRepository;
    }

    @PostConstruct
    void test() {
        this.gyrosRepository.insert(new Gyros("ham ham"));
        this.kebabRepository.saveAndFlush(new Kebab("yum yum"));
    }
}

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>2.2.2.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <groupId>org.example</groupId>
    <artifactId>stack</artifactId>
    <version>1.0-SNAPSHOT</version>
    <name>stackoverflow</name>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-mongodb</artifactId>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
    </dependencies>

</project>

Answer 3

I also faced the same kind of problem once. I had to connect my spring boot application to two different databases. One was Mongo db and other was Postgres db.

You can see that i have used both JPA as well as spring-boot-starter-data-mongodb. Still my project is running absolutely fine.Hope for you also it work successfully. There are suggestions over the internet to not use JPA but i am not able to use JPA repository without include JPA.

Here I am posting the solution which worked for me.

Hope it helps someone:

1. application.properties file:

   MONGODB (MongoProperties)

   spring.data.mongodb.uri=mongodb://XX.XX.XX.XX:27017/testdb

   #POSTGRES properties
       spring.datasource.platform=postgres
       spring.datasource.url= jdbc:postgresql://localhost:5432/database_name    
       spring.datasource.username=postgres_usr_name
       spring.datasource.password=postgres_pwd
       spring.jpa.properties.hibernate.jdbc.lob.non_contextual_creation=true
   

2. My pom dependencies:

   <dependencies>
   <dependency>
       <groupId>org.springframework.boot</groupId>
       <artifactId>spring-boot-starter-data-jpa</artifactId>
   </dependency>   
   <dependency>
       <groupId>org.postgresql</groupId>
       <artifactId>postgresql</artifactId>
   </dependency> 
   <dependency>
       <groupId>org.mongodb</groupId>
       <artifactId>mongo-java-driver</artifactId>
   </dependency> 
   <dependency>
       <groupId>org.springframework.boot</groupId>
       <artifactId>spring-boot-starter-data-mongodb</artifactId>
   </dependency>
   

3. To access my data Using Repositories:

   (i): MONGO REPOSITORY

     import org.springframework.data.mongodb.repository.MongoRepository;
       public interface MRepositories extends MongoRepository<YourEntityClass, String>{
           }
   

   (ii): JPA repository

   @Repository public interface PostGresRepo extends JpaRepository<TestEntity,Long> {}