ejb中开发jpa时，通过数据库表来生成实体类的时候，一个customer有一个cart表
这是购物车类
@Entity
@Table(name="cart")
public class Cart implements Serializable {
private static final long serialVersionUID = 1L;

@Id
@GeneratedValue(strategy=GenerationType.IDENTITY)
@Column(unique=true, nullable=false)
private int id;

@Column(nullable=false, precision=10)
private BigDecimal totalPrice;

@Column(nullable=false)
private int totalQuantity;

//bi-directional one-to-one association to Customer
@OneToOne
@JoinColumn(name="id", nullable=false, insertable=false, updatable=false)
private Customer customer;
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这是用户类
@Entity
@Table(name="customer")
public class Customer implements Serializable {
private static final long serialVersionUID = 1L;

@Id
@GeneratedValue(strategy=GenerationType.IDENTITY)
@Column(unique=true, nullable=false)
private int id;

@Lob()
private String autograph;

@Column(length=255)
private String email;

@Column(length=255)
private String gender;

@Lob()
@Column(name="img_url")
private String imgUrl;

@Column(length=255)
private String nickname;

@Column(length=255)
private String password;

@Column(length=255)
private String phone;

@Column(length=255)
private String username;

//bi-directional one-to-one association to Cart
@OneToOne(mappedBy="customer")
private Cart cart;

但是启动jboss时会出现如下错误，这是为什么？
org.hibernate.AnnotationException: Unknown mappedBy in: com.b2b.entities.Customer.cart, referenced property unknown: com.b2b.entities.Cart.customer