Как исправить ошибку в спринге?
Добавте JDBC драйвера в зависимости. В статье написано об этом.NOTE: I noticed that some of the readers are getting database connection issues. Notice that in my pom.xml, there is no database driver. That works for me because I have MySQL driver in tomcat lib directory and some DataSource connections configured with it. For any database connection related issues, either put the database driver in container lib or include that in pom.xml dependencies.
Если используете MySQL то это будет<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>6.0.4</version>
</dependency>
Добавьте к методу listPersons() аннотацию @Transaction.