<Resource name="jdbc/MyLocalDB"
  global="jdbc/MyLocalDB"
  auth="Container"
  type="javax.sql.DataSource"
  driverClassName="com.mysql.jdbc.Driver"
  url="jdbc:mysql://localhost:3306/demoData"
  username="root"
  password="root"
  maxActive="100"
  maxIdle="20"
  minIdle="5"
  maxWait="10000"/>

<ResourceLink name="jdbc/MyLocalDB"
            global="jdbc/MyLocalDB"
            auth="Container"
            type="javax.sql.DataSource" />

package com.tomcat.pool;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.sql.DataSource;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.jdbc.core.JdbcTemplate;

@SpringBootApplication
public class SpringJDBCConnectionPoolApp {

public static void main(String[] args) {
    SpringApplication.run(SpringJDBCConnectionPoolApp.class, args);
}


@Bean
public DataSource dataSource(){
    Context ctx = null;
    DataSource ds = null;
    try {
        ctx = new InitialContext();
        ds = (DataSource) ctx.lookup("java:/comp/env/jdbc/MyLocalDB");
    } catch (NamingException e) {
        System.out.println("dataSource not found!!!");
    }
    return ds;
}

@Bean
public JdbcTemplate jdbcTemplate(DataSource dataSource){
    return new JdbcTemplate(dataSource);
}
}