public class TenantRoutingDataSource extends AbstractRoutingDataSource {
    @Override
    protected Object determineCurrentLookupKey() {
        return TenantContext.getCurrentTenant();
    }
}
 
@Configuration
public class DataSourceConfig {
    @Bean
    public DataSource dataSource() {
        Map<Object, Object> targetDataSources = new HashMap<>();
        targetDataSources.put("TENANT_A", dataSourceA());
        targetDataSources.put("TENANT_B", dataSourceB());
        
        TenantRoutingDataSource routingDataSource = new TenantRoutingDataSource();
        routingDataSource.setTargetDataSources(targetDataSources);
        routingDataSource.setDefaultTargetDataSource(dataSourceA());
        return routingDataSource;
    }
}