我目前正在处理一个Sping Boot 应用程序，其中有两个实体，User和Account。Account实体与User之间是多对一的关系。下面是实体的基本结构：

@Table(name = "accounts")
@Entity
@Getter
@Setter
@NoArgsConstructor
public class Account {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    private String currency;
    private Double balance = 0.00;
    @Column(name = "created_at")
    private LocalDateTime createdAt = LocalDateTime.now();
    @ManyToOne(cascade = CascadeType.ALL)
    @JoinColumn(name = "user_id")
    private User user;
}

在我的服务类中，我有一个方法来创建一个与User关联的Account。下面是代码片段：

@Table(name = "users")
@Entity
@Getter
@Setter
@NoArgsConstructor
public class User {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    @Column(name = "first_name")
    private String firstName;
}

@Repository
public interface AccountRepository extends JpaRepository<Account, Long> {
//    List<Account> findByUser(User user);
}

    public void createAccount(User user, String currency) {
        Account account = new Account();
        account.setCurrency(currency);
        account.setUser(user);

        accountRepository.save(account);
    }

然而，当我运行我的应用程序时，我遇到了以下错误：

2023-10-10T21:44:06.549+02:00 ERROR 9340 --- [           main] o.s.boot.SpringApplication               : Application run failed

java.lang.IllegalStateException: Failed to execute CommandLineRunner
    at org.springframework.boot.SpringApplication.callRunner(SpringApplication.java:777) ~[spring-boot-3.1.4.jar:3.1.4]
    at org.springframework.boot.SpringApplication.callRunners(SpringApplication.java:758) ~[spring-boot-3.1.4.jar:3.1.4]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:322) ~[spring-boot-3.1.4.jar:3.1.4]
    at pl.bartoszmech.BankApp.Application.main(Application.java:31) ~[classes/:na]
Caused by: org.springframework.dao.InvalidDataAccessApiUsageException: detached entity passed to persist: pl.bartoszmech.BankApp.model.User

我知道此错误与尝试持久化分离的实体有关，但我不确定如何正确地将用户与帐户关联并解决此问题。
有人能指导我如何解决这个问题，并确保用户实体与帐户实体正确关联时，保存在Sping Boot 与Hibernate？任何见解或解决方案将不胜感激。谢谢你，谢谢！