Context
<?xml version = "1.0" encoding = "UTF-8"?>
<Context>
  <Resource name="jdbc/shop_MYSQL"
			global="jdbc/shop_MYSQL"
  			auth="Container"
  			type="javax.sql.DataSource"
			maxActive="100" maxIdle="30" maxWait="10000"
			username="root"
			driverClassName="com.mysql.jdbc.Driver"
			defaultAutoCommit="false"
			defaultTransactionIsolation="READ_COMMITTED"
			url="jdbc:mysql://localhost:3306/shop"/>
</Context>

web.xml
	</context-param>
	<resource-ref>
		<res-ref-name>jdbc/shop_MYSQL</res-ref-name>
		<res-type>javax.sql.DataSource</res-type>
		<res-auth>Container</res-auth>
	</resource-ref>

Pom
	<dependency>
			<groupId>mysql</groupId>
			<artifactId>mysql-connector-java</artifactId>
			<version>8.0.11</version>
		</dependency>
		<dependency>
			<groupId>org.apache.tomcat</groupId>
			<artifactId>tomcat-jdbc</artifactId>
			<version>8.0.20</version>
		</dependency>

       code:
        Context ctx = new InitialContext();
        ds  = (DataSource) ctx.lookup("java:comp/env/jdbc/shop_MYSQL");
        Connection conn = ds.getConnection();

org.apache.tomcat.dbcp.dbcp.SQLNestedException: Cannot create JDBC driver of class '' for connect URL 'null'