import javax.transaction.Transactional;

import org.springframework.data.jpa.repository.JpaRepository;

import com.crm.model.User;

@Transactional
public interface UserDao extends JpaRepository<User, Long> {

  public User findByEmail(String email);

}

import javax.transaction.Transactional;

import com.crm.model.User;

@Transactional
public interface UserDaoCustom {

    public User customMethod(String email);

}

import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
import javax.transaction.Transactional;

import org.springframework.stereotype.Repository;

import com.crm.model.User;

@Transactional
@Repository
public class UserDaoCustomImpl implements UserDaoCustom {

    @PersistenceContext
    EntityManager em;

    public User customMethod(String email) {
        return (User) em.createQuery("select 1", User.class);
    }

}

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

import com.crm.dao.UserDaoCustom;
import com.crm.model.User;

@Controller
public class UserController {

    @Autowired
    private UserDaoCustom userDao;
...

spring.datasource.url = jdbc:mysql://domain:3306/server?useSSL=false
spring.datasource.username = user
spring.datasource.password = password
spring.datasource.testWhileIdle = true
spring.datasource.validationQuery = SELECT 1
spring.jpa.show-sql = true
spring.jpa.hibernate.ddl-auto = update
spring.jpa.hibernate.naming-strategy = org.hibernate.cfg.ImprovedNamingStrategy
spring.jpa.properties.hibernate.dialect = org.hibernate.dialect.MySQL5Dialect