使用jpa出现的持久化级联问题[跪求解答]


package org.neusoft.bean.shopping;import java.util.ArrayList;
import java.util.Date;
import java.util.List;import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.EnumType;
import javax.persistence.Enumerated;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.OneToMany;
import javax.persistence.OneToOne;
import javax.persistence.Temporal;
import javax.persistence.TemporalType;import org.neusoft.bean.user.Buyer;
import org.neusoft.bean.user.Gender;/**
 * 订单配送信息
 */@Entity(name="order_")
public class Order {
/* 订单号 */
private String orderid = null; /* 送货信息 */
private OrderDeliver deliver = null;
/* 联系人信息 */
private OrderContact contact = null;         ........................... /** optional 指定配送信息是否一定存在, 如果有不要配送的产品,可以设置为true,false为必须有**/
@OneToOne(cascade={CascadeType.ALL},optional=false)
@JoinColumn(name="deliverid")
public OrderDeliver getDeliver() {
return deliver;
}
public void setDeliver(OrderDeliver deliver) {
this.deliver = deliver;
}
@OneToOne(cascade={CascadeType.ALL},optional=false)
@JoinColumn(name="contactid")
public OrderContact getContact() {
return contact;
}
public void setContact(OrderContact contact) {
this.contact = contact;
}

} order.setDeliver(cart.getDeliver());
order.setContact(cart.getContact());
                            save(order);当我在saveorder的时候deliver的已经在数据库中存在,不能能让order不用保存deliver实体,而直接deliver对象的id即可.