使用Spring的Hibernate 4实体映射

Question

I've got 2 entity classes as follows:

@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...
}

AND

@Entity
@Table(name = "USER_PERM")
public class UserPermission implements Serializable {

    private static final long serialVersionUID = 1L;

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

    @Column(name = "PERM", unique = true, length = 255, nullable = false)
    private String authority;
// getters and setters...
}

Now when I create an object of UserAccount and try to save it using the session factory it gives me the following error:

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

Shouldn't the UserPermission class be saved by itself?? This is the code that is used to persist:

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

Answer 1

除非您指定级联选项，否则不会。