(For simplicity sake,
  domain : localhost:8080 ---> hem1 DB
  domain : 127.0.0.1:8080 ---> hem2 DB
)

public class MyRoutingDataSource extends AbstractRoutingDataSource{
        @Override
        protected Object determineCurrentLookupKey() {

        /*
         * this is derived from threadlocal set by filter for each web
         * request
         */
             return SessionUtil.getDB();
        }
    }

package com.hemant.basic.dataSource;

    import java.beans.PropertyVetoException;
    import java.util.HashMap;
    import java.util.Map;

    import javax.naming.ConfigurationException;
    import javax.sql.DataSource;

    import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.Configuration;

    import com.mchange.v2.c3p0.ComboPooledDataSource;

    @Configuration
    public class DBConfig {

        @Bean(name = "dataSource")
        public DataSource dataSource() throws PropertyVetoException,
                ConfigurationException {
            MyRoutingDataSource routingDB = new MyRoutingDataSource();
            Map<Object, Object> targetDataSources = datasourceList();

// hem1 is the default target DB
routingDB.setDefaultTargetDataSource(targetDataSources.get(1));
            routingDB.setTargetDataSources(targetDataSources);
            routingDB.afterPropertiesSet();
            return routingDB;
        }

        private Map<Object, Object> datasourceList() throws PropertyVetoException,
                ConfigurationException {
            final Map<Object, Object> datasources = new HashMap<Object, Object>();
            ComboPooledDataSource datasource = null;
            for (int id = 1; id <= 2; id++) {
                datasource = getDatasource(id);
                datasources.put(id, datasource);
            }
            return datasources;
        }

        private ComboPooledDataSource getDatasource(int id)
                throws PropertyVetoException, ConfigurationException {
            ComboPooledDataSource datasource = new ComboPooledDataSource();

            // set the connection pool properties
            datasource.setJdbcUrl("jdbc:postgresql://localhost/hem" + id);
            datasource.setUser("hemant");
            datasource.setPassword("");
            datasource.setDriverClass("org.postgresql.Driver");
            datasource.setMaxPoolSize(30);
            datasource.setInitialPoolSize(10);
            datasource.setMinPoolSize(10);

            return datasource;
        }
    }

# Hibernate ddl auto (create, create-drop, update)
spring.jpa.hibernate.ddl-auto = update

[main] org.hibernate.tool.hbm2ddl.SchemaUpdate  : HHH000228: Running hbm2ddl schema update
[main] org.hibernate.tool.hbm2ddl.SchemaUpdate  : HHH000102: Fetching database metadata
[main] org.hibernate.tool.hbm2ddl.SchemaUpdate  : HHH000396: Updating schema
[main] java.sql.DatabaseMetaData                : HHH000262: Table not found: users
[main] java.sql.DatabaseMetaData                : HHH000262: Table not found: users
[main] java.sql.DatabaseMetaData                : HHH000262: Table not found: users
[main] org.hibernate.tool.hbm2ddl.SchemaUpdate  : HHH000232: Schema update complete`enter code here`