使用Spring进行Hibernate 4实体映射

我有两个实体类，如下所示：

@Entity
@Table(name = "USER_ACCT")
public class UserAccount implements Serializable{

private static final long serialVersionUID = 1L;

@Id
@GeneratedValue(strategy=GenerationType.SEQUENCE, generator="USER_ACCT_ID_SEQ")
@SequenceGenerator(name="USER_ACCT_ID_SEQ", sequenceName="USER_ACCT_ID_SEQ")
@Column(name = "USER_ACCT_ID")
protected Long id;

@Basic(optional = false)
@Column(length = 50, unique = true)
private String username;

@Basic(optional = false)
@Column(length = 128, nullable = false)
private String password;

@ManyToMany(targetEntity = UserPermission.class)
@JoinTable(name = "USER_ACCT_PERM",
        joinColumns         = @JoinColumn(name = "USER_ACCT_ID"),
        inverseJoinColumns  = @JoinColumn(name = "USER_PERM_ID", referencedColumnName = "USER_PERM_ID"))
private Set<UserPermission> permissions;

// getters and setters...
}

现在，当我创建UserAccount的对象并尝试使用会话工厂保存它时，会出现以下错误：

org.hibernate.TransientObjectException: object references an unsaved transient instance - save the transient instance before flushing: com.rpm.domain.UserPermission

UserPermission类不应该自己保存吗？？ 这是用于持久化的代码：

@Transactional
    public void addUser(){
                Set<UserPermission> permissions = new HashSet<UserPermission>();
    permissions.add(new UserPermission("ROLE_ADMIN"););
        sessionFactory.getCurrentSession().save(new UserAccount("admin", "d033e22ae348aeb5660fc2140aec35850c4da997", permissions));
    }

@Transactional
public void addUser（）{
Set permissions=new HashSet（）；
添加（新用户权限（“角色管理”）；
保存（新用户帐户（“管理员”，“d033e22ae348aeb5660fc2140aec35850c4da997”，权限））；
}

除非您指定了级联选项，否则不会

除非您指定级联选项，否则不会

也许，如果您发布用于创建和持久化实体的代码，我们可以更好地帮助您。如果您发布用于创建和持久化实体的代码，我们可以更好地帮助您

@Transactional
    public void addUser(){
                Set<UserPermission> permissions = new HashSet<UserPermission>();
    permissions.add(new UserPermission("ROLE_ADMIN"););
        sessionFactory.getCurrentSession().save(new UserAccount("admin", "d033e22ae348aeb5660fc2140aec35850c4da997", permissions));
    }