Hibernate MySQL 查询错误“Join On 中的未知列”

解决Hibernate MySQL查询错误“Join On中的未知列”

java
@Entity
@Table(name = "user")
public class User {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    @Column(name = "username")
    private String username;
    // other fields, getters and setters
}
@Entity
@Table(name = "order")
public class Order {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    @ManyToOne
    @JoinColumn(name = "user_id")
    private User user;
    // other fields, getters and setters
}
public class OrderDao {
    public List findOrdersByUsername(String username) {
        Session session = HibernateUtil.getSessionFactory().openSession();
        CriteriaBuilder cb = session.getCriteriaBuilder();
        CriteriaQuery cq = cb.createQuery(Order.class);
        Root root = cq.from(Order.class);
        Join userJoin = root.join("user");
        cq.where(cb.equal(userJoin.get("username"), username));
        TypedQuery query = session.createQuery(cq);
        List orders = query.getResultList();
        session.close();
        return orders;
    }
}