mysql jpa取不到数据库

<persistence xmlns="http://xmlns.jcp.org/xml/ns/persistence" version="2.1">
    <persistence-unit name="myPersistenceUnit">
        <provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>
        <class>com.example.User</class>
        <properties>
            <property name="javax.persistence.jdbc.url" value="jdbc:mysql://localhost:3306/mydatabase"/>
            <property name="javax.persistence.jdbc.user" value="username"/>
            <property name="javax.persistence.jdbc.password" value="password"/>
            <property name="hibernate.dialect" value="org.hibernate.dialect.MySQLDialect"/>
            <property name="hibernate.connection.driver_class" value="com.mysql.cj.jdbc.Driver"/>
        </properties>
    </persistence-unit>
</persistence>

import javax.persistence.*;

@Entity
@Table(name = "users")
public class User {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @Column(name = "username")
    private String username;

    // Getters and setters
}

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
import javax.transaction.Transactional;
import java.util.List;

@Service
public class UserService {
    @PersistenceContext
    private EntityManager entityManager;

    @Transactional
    public List<User> getAllUsers() {
        return entityManager.createQuery("SELECT u FROM User u", User.class).getResultList();
    }
}