Repository take solrtemplate to execute solr operations. Since we have multiple cores so we need to create multiple template and multiple repositories for each core. Following example explains it with 2 solr core

Repository and custom implementation for core1:

public interface ICore1CustomDao {

	  List<Core1> findCore1Data();
}

public interface Core1Repository extends SolrCrudRepository<Core1, String> {

}

public class Core1DaoImpl implements ICore1CustomDao {

	@Autowired
    private SolrTemplate core1Template;

    public EventRepositoryImpl(SolrTemplate core1Template) {
        this.core1Template = core1Template;
    }

    @Override
    public List<Core1> findCore1Data() {
        return core1Template.queryForPage(new SimpleQuery("*:*"), Core1.class);
    }

}

Do same for Core2 repositories.

Configure solr as:

@Configuration
public class Application {
	
	@Bean
	public SolrServerFactory solrServerFactory() {
		return new MulticoreSolrServerFactory(new HttpSolrServer("http://localhost:8983/solr"));
	}
	
	@Bean
	public SolrTemplate core1Template() throws Exception {
		SolrTemplate solrTemplate = new SolrTemplate(solrServerFactory());
	    solrTemplate.setSolrCore("core1");
	    return solrTemplate;
	}
	
	@Bean
	public Core1Repository core1Repository() throws Exception {
	    return new SolrRepositoryFactory(core1Template())
	      .getRepository(Core1Repository.class, new Core1DaoImpl(core1Template()));
	}
	
	@Bean
	public SolrTemplate core2Template() throws Exception {
		SolrTemplate solrTemplate = new SolrTemplate(solrServerFactory());
	    solrTemplate.setSolrCore("core2");
	    return solrTemplate;
	}
	
	@Bean
	public Core2Repository core2Repository() throws Exception {
	    return new SolrRepositoryFactory(core2Template())
	      .getRepository(Core2Repository.class, new Core2DaoImpl(core2Template()));
	}
	
}

Its done.