import org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource;

public class MultitenantDataSource extends AbstractRoutingDataSource {
    @Override
    protected Object determineCurrentLookupKey() {
        return TenantContext.getCurrentTenant();

    }
}

public class TenantContext {
    private static ThreadLocal<Object> currentTenant = ThreadLocal.withInitial(() -> "TenantTwo") ;

    public static void setCurrentTenant(Object tenant) {
        currentTenant.set(tenant);
    }

    public static Object getCurrentTenant() {
        return currentTenant.get();
    }
}

import com.zaxxer.hikari.HikariDataSource;
import javax.sql.DataSource;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.autoconfigure.jdbc.DataSourceProperties;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource;
import org.springframework.context.annotation.Configuration;
import ebi.zmap.MultitenantDataSource; // здесь импортируется ваш класс из первого файла
import java.io.*;
import java.nio.file.Paths;
import java.util.*;
import java.util.Properties;

@Configuration
public class MultitenantConfiguration {

    @Autowired
    private DataSourceProperties properties;

    /**
     * Defines the data source for the application
     * @return
     */
    @Bean
    @ConfigurationProperties(
            prefix = "spring.datasource"
    )
    public DataSource dataSource() {
      AbstractRoutingDataSource dataSource = new MultitenantDataSource();

     Map<Object,Object> targetDataSources = new HashMap<>();

     targetDataSources.put("TenantOne", tenantOne());
     targetDataSources.put("TenantTwo", tenantTwo());
     targetDataSources.put(null, tenantOne());

     dataSource.setTargetDataSources(targetDataSources);

     dataSource.afterPropertiesSet();

     return dataSource;
 }

 public DataSource tenantOne() {

     HikariDataSource dataSource = new HikariDataSource();

     dataSource.setInitializationFailTimeout(0);
     dataSource.setMaximumPoolSize(5);
     dataSource.setDataSourceClassName("com.mysql.jdbc.jdbc2.optional.MysqlDataSource");
     dataSource.addDataSourceProperty("url", "jdbc:mysql://127.0.0.1:3306/annotrack");
     dataSource.addDataSourceProperty("user", "root");
     dataSource.addDataSourceProperty("password", "");

     return dataSource;
 }

 public DataSource tenantTwo() {

     HikariDataSource dataSource = new HikariDataSource();

     dataSource.setInitializationFailTimeout(0);
     dataSource.setMaximumPoolSize(5);
     dataSource.setDataSourceClassName("com.mysql.jdbc.jdbc2.optional.MysqlDataSource");
     dataSource.addDataSourceProperty("url", "jdbc:mysql://127.0.0.1:3306/annotrackm");
     dataSource.addDataSourceProperty("user", "root");
     dataSource.addDataSourceProperty("password", "");

     return dataSource;
    }

    /**
     * Creates the default data source for the application
     * @return
     */
    private DataSource defaultDataSource() {
      HikariDataSource dataSource = new HikariDataSource();

      dataSource.setInitializationFailTimeout(0);
      dataSource.setMaximumPoolSize(5);
      dataSource.setDataSourceClassName("com.mysql.cj.jdbc.Driver");
      dataSource.addDataSourceProperty("url", "jdbc:mysql://193.62.52.185:3306/annotrack");
      dataSource.addDataSourceProperty("user", "admin");
      dataSource.addDataSourceProperty("password", "interestingtimes");

      return dataSource;
    }
}

TenantContext.setCurrentTenant(db);