How can i setup Spring Boot with two datasources (MapRepository and H2 JPARepository)?

Question

I'm trying to set up a spring boot project with two datasources. First datasource would be a H2 Database and second a MapRepository. Both repositories would share the same entity.

I could manage to setup a project with two H2 databases, but when I try to setup a MapRepository instead of the second H2 datasource I get the following error:

  .   ____          _            __ _ _
 /\ / ___'_ __ _ _(_)_ __  __ _    
( ( )\___ | '_ | '_| | '_ / _` |    
 \/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::                (v2.4.0)

2021-01-12 10:57:16.610  INFO 26672 --- [           main] ch.getonline.springtestapp.App           : Starting App using Java 15.0.1 on nbbetina1 with PID 26672 (C:UsersBetinaHiestandeclipse20-workspacespring-test-appargetclasses started by BetinaHiestand in C:UsersBetinaHiestandeclipse20-workspacespring-test-app)
2021-01-12 10:57:16.612  INFO 26672 --- [           main] ch.getonline.springtestapp.App           : The following profiles are active: dev
2021-01-12 10:57:17.070  INFO 26672 --- [           main] .s.d.r.c.RepositoryConfigurationDelegate : Multiple Spring Data modules found, entering strict repository configuration mode!
2021-01-12 10:57:17.070  INFO 26672 --- [           main] .s.d.r.c.RepositoryConfigurationDelegate : Bootstrapping Spring Data Map repositories in DEFAULT mode.
2021-01-12 10:57:17.092  INFO 26672 --- [           main] .RepositoryConfigurationExtensionSupport : Spring Data Map - Could not safely identify store assignment for repository candidate interface ch.getonline.springtestapp.storage.repositories.map.MapRepository. If you want this repository to be a Map repository, consider extending one of the following types with your repository: org.springframework.data.keyvalue.repository.KeyValueRepository.
2021-01-12 10:57:17.092  INFO 26672 --- [           main] .s.d.r.c.RepositoryConfigurationDelegate : Finished Spring Data repository scanning in 15 ms. Found 0 Map repository interfaces.
2021-01-12 10:57:17.094  INFO 26672 --- [           main] .s.d.r.c.RepositoryConfigurationDelegate : Multiple Spring Data modules found, entering strict repository configuration mode!
2021-01-12 10:57:17.094  INFO 26672 --- [           main] .s.d.r.c.RepositoryConfigurationDelegate : Bootstrapping Spring Data JPA repositories in DEFAULT mode.
2021-01-12 10:57:17.111  INFO 26672 --- [           main] .s.d.r.c.RepositoryConfigurationDelegate : Finished Spring Data repository scanning in 14 ms. Found 1 JPA repository interfaces.
2021-01-12 10:57:17.654  INFO 26672 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat initialized with port(s): 8080 (http)
2021-01-12 10:57:17.661  INFO 26672 --- [           main] o.apache.catalina.core.StandardService   : Starting service [Tomcat]
2021-01-12 10:57:17.661  INFO 26672 --- [           main] org.apache.catalina.core.StandardEngine  : Starting Servlet engine: [Apache Tomcat/9.0.39]
2021-01-12 10:57:17.758  INFO 26672 --- [           main] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2021-01-12 10:57:17.758  INFO 26672 --- [           main] w.s.c.ServletWebServerApplicationContext : Root WebApplicationContext: initialization completed in 1105 ms
2021-01-12 10:57:17.976  INFO 26672 --- [           main] o.s.b.a.h2.H2ConsoleAutoConfiguration    : H2 console available at '/dbadmin'. Database available at 'jdbc:h2:mem:db1dev'
2021-01-12 10:57:18.058  INFO 26672 --- [           main] o.hibernate.jpa.internal.util.LogHelper  : HHH000204: Processing PersistenceUnitInfo [name: default]
2021-01-12 10:57:18.099  INFO 26672 --- [           main] org.hibernate.Version                    : HHH000412: Hibernate ORM core version 5.4.23.Final
2021-01-12 10:57:18.198  INFO 26672 --- [           main] o.hibernate.annotations.common.Version   : HCANN000001: Hibernate Commons Annotations {5.1.2.Final}
2021-01-12 10:57:18.324  INFO 26672 --- [           main] org.hibernate.dialect.Dialect            : HHH000400: Using dialect: org.hibernate.dialect.H2Dialect
Hibernate: 
    
    drop table if exists "BasicEntity" CASCADE 
Hibernate: 
    
    create table "BasicEntity" (
       "DNA" binary not null,
        "id" varchar(255),
        "type" varchar(255),
        primary key ("DNA")
    )
2021-01-12 10:57:18.759  INFO 26672 --- [           main] o.h.e.t.j.p.i.JtaPlatformInitiator       : HHH000490: Using JtaPlatform implementation: [org.hibernate.engine.transaction.jta.platform.internal.NoJtaPlatform]
2021-01-12 10:57:18.765  INFO 26672 --- [           main] j.LocalContainerEntityManagerFactoryBean : Initialized JPA EntityManagerFactory for persistence unit 'default'
2021-01-12 10:57:18.787  INFO 26672 --- [           main] ch.getonline.springtestapp.App           : SpringTestApplication is starting...
2021-01-12 10:57:18.931  WARN 26672 --- [           main] ConfigServletWebServerApplicationContext : Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'appContext': Unsatisfied dependency expressed through field 'entityStorage'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'entityStorageHandler' defined in file [C:UsersBetinaHiestandeclipse20-workspacespring-test-appargetclasseschgetonlinespringtestappstoragehandlersEntityStorageHandler.class]: Unsatisfied dependency expressed through constructor parameter 2; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'ch.getonline.springtestapp.storage.repositories.map.MapRepository' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {}
2021-01-12 10:57:18.931  INFO 26672 --- [           main] j.LocalContainerEntityManagerFactoryBean : Closing JPA EntityManagerFactory for persistence unit 'default'
2021-01-12 10:57:18.933  INFO 26672 --- [           main] o.apache.catalina.core.StandardService   : Stopping service [Tomcat]
2021-01-12 10:57:18.944  INFO 26672 --- [           main] ConditionEvaluationReportLoggingListener : 

Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2021-01-12 10:57:18.956 ERROR 26672 --- [           main] o.s.b.d.LoggingFailureAnalysisReporter   : 

***************************
APPLICATION FAILED TO START
***************************

Description:

Parameter 2 of constructor in ch.getonline.springtestapp.storage.handlers.EntityStorageHandler required a bean of type 'ch.getonline.springtestapp.storage.repositories.map.MapRepository' that could not be found.

The injection point has the following annotations:
    - @org.springframework.beans.factory.annotation.Autowired(required=true)


Action:

Consider defining a bean of type 'ch.getonline.springtestapp.storage.repositories.map.MapRepository' in your configuration.

I already tried to add the ComponentScan and add a repository annotation to the MapRepository, but couldn't figure out why no bean was created for it. Both repositories are in seperate packages which are set as basePackages for the EnableMapRepositories/EnableJpaRepositories annotation. For the SQLRepository I created a configuration class with the driver properties etc. I am not sure if something like this would also be needed for the MapRepositories and couldn't find helpful documentation about it.

I am not really experienced with Spring Boot therefore the first question would be if its possible to have a setup like this? And if yes how am I supposed to configure it?

Application start:

@SpringBootApplication
@ComponentScan (basePackages = {"ch.getonline.springtestapp"})
@EntityScan("ch.getonline.springtestapp.entity.types")
@EnableMapRepositories(basePackages = "ch.getonline.springtestapp.storage.repositories.map")
@EnableJpaRepositories(basePackages = "ch.getonline.springtestapp.storage.repositories.sql", entityManagerFactoryRef = "sqlDatabaseEntityManager", transactionManagerRef = "sqlDatabaseTransactionManager")
public class App  {
    
    // Logger setup (Per class) 
    private static final Logger log = LoggerFactory.getLogger(App.class);
            
    /*
     *  Application start
     */
    public static void main(String[] args) {
        ApplicationContext ctx = SpringApplication.run(App.class, args);
        System.out.println("App context in main: " + ctx.getDisplayName());
    }
    

MapRepository:

package ch.getonline.springtestapp.storage.repositories.map;



import org.springframework.stereotype.Repository;

import ch.getonline.springtestapp.storage.repositories.EntityRepository;

@Repository("mapRepository")
public interface MapRepository extends EntityRepository {

}

EntityRepository:

package ch.getonline.springtestapp.storage.repositories;

import org.springframework.data.repository.CrudRepository;
import org.springframework.data.repository.NoRepositoryBean;

import ch.getonline.springtestapp.entity.types.BasicEntity;

@NoRepositoryBean
public interface EntityRepository extends CrudRepository<BasicEntity, Long>{
    //Entity findByUuid(UUID id);
}

StorageHandler in which I tried to access both repositories:

    package ch.getonline.springtestapp.storage.handlers;
    
    import java.util.HashMap;
    import java.util.Map;
    import java.util.Map.Entry;
    import java.util.UUID;
    
    import org.slf4j.Logger;
    import org.slf4j.LoggerFactory;
    import org.springframework.stereotype.Component;
    
    
    import ch.getonline.springtestapp.AppContext;
    import ch.getonline.springtestapp.entity.attribute.Attribute;
    import ch.getonline.springtestapp.entity.types.BasicEntity;
    import ch.getonline.springtestapp.storage.StorageHandler;
    import ch.getonline.springtestapp.storage.repositories.EntityRepository;
    import ch.getonline.springtestapp.storage.repositories.map.MapRepository;
    import ch.getonline.springtestapp.storage.repositories.sql.SQLRepository;
    
    
    
    
    
    /** Entity Storage
     * <br>
     * 
     * - Coordinates saving, loading, updating of Entities over different Repositories
     * 
     * 
     * @author sigi
     *
     */
    
    @Component
    public class EntityStorageHandler implements StorageHandler<BasicEntity, Long> {
        
        
        // Logger
        private static final Logger log = LoggerFactory.getLogger(EntityStorageHandler.class);
    
        private final AppContext app;
        private final Map<String, EntityRepository> repos;
        EntityStorageHandler(AppContext app,  SQLRepository sqlRepo, MapRepository mapRepo) {
            this.app = app;
            this.repos = new HashMap<String, EntityRepository>();
            this.repos.put("sql", sqlRepo);
            this.repos.put("map", mapRepo);
        }
        
        
        
        //StorageHandler start hook
        public void run(String... args) throws Exception {
            
            //Print all configs for the key app in the config
            StringBuilder appConfig = new StringBuilder();
            for(Entry<String, Object> entry : this.app.getConfig().entrySet()) {
                appConfig.append("
key: " + entry.getKey() + " value: " + entry.getValue());
            }
        

Answer 1

As written in my comment, it's quite unusual to use two different datasources with one spring boot service. But here are cases where this might be necessary, and here is how to achieve it in a clean way:

Keep in mind, my answer is mostly taken from that Baeldung tutorial

Consider having a datasource like this:

spring.datasource.jdbcUrl = [url]
spring.datasource.username = [username]
spring.datasource.password = [password]

Now, we want to add a second one, preferably with the same syntax:

spring.second-datasource.jdbcUrl = [url]
spring.second-datasource.username = [username]
spring.second-datasource.password = [password]

To use both configurations simoultanously, we just create two configuration classes with a Datasource Bean - pay attention to the prefix annotation:

@Configuration
@PropertySource({"classpath:persistence-multiple-db-boot.properties"})
@EnableJpaRepositories(
  basePackages = "com.baeldung.multipledb.dao.user",
  entityManagerFactoryRef = "userEntityManager",
  transactionManagerRef = "userTransactionManager")
public class PersistenceUserAutoConfiguration {
    
    @Primary
    @Bean
    @ConfigurationProperties(prefix="spring.datasource")
    public DataSource userDataSource() {
        return DataSourceBuilder.create().build();
    }
    // userEntityManager bean 

    // userTransactionManager bean
}


@Configuration
@PropertySource({"classpath:persistence-multiple-db-boot.properties"})
@EnableJpaRepositories(
  basePackages = "com.baeldung.multipledb.dao.product", 
  entityManagerFactoryRef = "productEntityManager", 
  transactionManagerRef = "productTransactionManager")
public class PersistenceProductAutoConfiguration {
   
    @Bean
    @ConfigurationProperties(prefix="spring.second-datasource")
    public DataSource productDataSource() {
        return DataSourceBuilder.create().build();
    }
   
    // productEntityManager bean 

    // productTransactionManager bean
}

You could imo just create one configuration class and provide both beans in that one.

For more information see Spring JPA – Multiple Databases