使用MySQL和Java CommandLineRunner实现Spring对象保存问题

<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
</dependency>

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>

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

    private String name;
    private String email;

    // 省略构造方法、getter和setter
}

@Component
public class DataInitializer implements CommandLineRunner {
    private final UserRepository userRepository;

    public DataInitializer(UserRepository userRepository) {
        this.userRepository = userRepository;
    }

    @Override
    public void run(String... args) throws Exception {
        // 创建一个User对象并保存到数据库
        User user = new User();
        user.setName("John Doe");
        user.setEmail("john.doe@example.com");
        userRepository.save(user);
    }
}

@Repository
public interface UserRepository extends JpaRepository<User, Long> {
}

spring.datasource.url=jdbc:mysql://localhost:3306/mydatabase
spring.datasource.username=root
spring.datasource.password=123456
spring.jpa.hibernate.ddl-auto=update