需求：订单和商品表
（分析：一个订单针对多个商品表，一个商品也可以针对多个订单，其中订单里面有多个订单详情，一个订单详情对应一个商品！简单的来说一个订单详情和商品是一对一的关系！多对多分解成了一对多和一对多）
- SQL语句：
select
u.id uid,u.user_name,u.password,u.name,u.age,u.sex,u.birthday,u.created,u.updated,o.id
oid,o.user_id,o.order_number,od.id odid,od.order_id,od.item_id,od.total_price,od.status,
i.id iid,i.item_name,i.item_price,i.item_detail
from tb_user u,tb_order o,tb_orderdetail od,tb_item i
where u.id = o.user_id and o.id = od.order_id and i.id = od.item_id and o.order_number =
#{orderNumber}
- 实体类：（订单 一对多 订单详情 一对一 商品）
订单的实体类：
package com.hisoft.pojo;
import java.util.List;
public class Order {
int id;
long userId;
String orderNumber;
User user;
List<OrderDetail> olist;
public List<OrderDetail> getOlist() {
return olist;
}
public void setOlist(List<OrderDetail> olist) {
this.olist = olist;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public long getUserId() {
return userId;
}
public void setUserId(long userId) {
this.userId = userId;
}
public String getOrderNumber() {
return orderNumber;
}
public void setOrderNumber(String orderNumber) {
this.orderNumber = orderNumber;
}
public User getUser() {
return user;
}
public void setUser(User user) {
this.user = user;
}
public Order(int id, long userId, String orderNumber, User user) {
super();
this.id = id;
this.userId = userId;
this.orderNumber = orderNumber;
this.user = user;
}
public Order() {
super();
// TODO Auto-generated constructor stub
}
@Override
public String toString() {
return "Order [id=" + id + ", userId=" + userId + ", orderNumber=" + orderNumber + ", user=" + user + ", olist="
+ olist + "]";
}
}
订单详情实体类：（实际上和商品是一对一的管理，所有需要在里面创建一个商品的对象实现一对一）
package com.hisoft.pojo;
public class OrderDetail {
int id;
int orderId;
int itemId;
double totalPrice;
int status;
Item item;
public Item getItem() {
return item;
}
public void setItem(Item item) {
this.item = item;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public int getOrderId() {
return orderId;
}
public void setOrderId(int orderId) {
this.orderId = orderId;
}
public int getItemId() {
return itemId;
}
public void setItemId(int itemId) {
this.itemId = itemId;
}
public double getTotalPrice() {
return totalPrice;
}
public void setTotalPrice(double totalPrice) {
this.totalPrice = totalPrice;
}
public int getStatus() {
return status;
}
public void setStatus(int status) {
this.status = status;
}
public OrderDetail(int id, int orderId, int itemId, double totalPrice, int status) {
super();
this.id = id;
this.orderId = orderId;
this.itemId = itemId;
this.totalPrice = totalPrice;
this.status = status;
}
public OrderDetail() {
super();
// TODO Auto-generated constructor stub
}
@Override
public String toString() {
return "OrderDetail [id=" + id + ", orderId=" + orderId + ", itemId=" + itemId + ", totalPrice=" + totalPrice
+ ", status=" + status + ", item=" + item + "]";
}
}
商品的实体类
package com.hisoft.pojo;
public class Item {
int id;
String itemName;
float itemPrice;
String itemDetail;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getItemName() {
return itemName;
}
public void setItemName(String itemName) {
this.itemName = itemName;
}
public float getItemPrice() {
return itemPrice;
}
public void setItemPrice(float itemPrice) {
this.itemPrice = itemPrice;
}
public String getItemDetail() {
return itemDetail;
}
public void setItemDetail(String itemDetail) {
this.itemDetail = itemDetail;
}
public Item(int id, String itemName, float itemPrice, String itemDetail) {
super();
this.id = id;
this.itemName = itemName;
this.itemPrice = itemPrice;
this.itemDetail = itemDetail;
}
public Item() {
super();
// TODO Auto-generated constructor stub
}
@Override
public String toString() {
return "Item [id=" + id + ", itemName=" + itemName + ", itemPrice=" + itemPrice + ", itemDetail=" + itemDetail
+ "]";
}
}
- 创建接口
public interface OrderMapper {
Order getOrderUserDetailItemInfo(@Param("orderNumber")String ordernumber);
}
- 在OrderMapper.xml里面书写sql语句
//这里注意一点这个resultMap里面继承了一对一的resultMap（哪里不太懂了 查看下一对多，里面有对里面的属性进行解释）
<resultMap type="Order" id="OrderUserDetailItemInfo"
autoMapping="true" extends="OrderUserInfo">
<collection property="olist" javaType="List"
ofType="OrderDetail">
<id column="odid" property="id" />
<association property="item" javaType="Item">
<id column="iid" property="id" />
</association>
</collection>
</resultMap>
<select id="getOrderUserDetailItemInfo"
resultMap="OrderUserDetailItemInfo">
select
u.id uid,u.user_name,u.password,u.name,u.age,u.sex,u.birthday,u.created,u.updated,o.id
oid,o.user_id,o.order_number,od.id odid,od.order_id,od.item_id,od.total_price,od.status,
i.id iid,i.item_name,i.item_price,i.item_detail
from tb_user u,tb_order o,tb_orderdetail od,tb_item i
where u.id = o.user_id and o.id = od.order_id and i.id = od.item_id and o.order_number =
#{orderNumber}
</select>
