Mybatis一对多关联映射实例

Mybatis一对多关联映射实例

定义实体类

用户实体

package com.hl.myabtis.first.beas;

import java.util.Date;

public class User {

private int id;
private String username;
private char sex;
private Date birthday;
private String address;
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public char getSex() {
return sex;
}
public void setSex(char sex) {
this.sex = sex;
}
public Date getBirthday() {
return birthday;
}
public void setBirthday(Date birthday) {
this.birthday = birthday;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
@Override
public String toString() {
return "User [id=" + id + ", username=" + username + ", sex=" + sex
+ ", birthday=" + birthday + ", address=" + address + "]";
}

}

订单实体

package com.hl.myabtis.first.beas;

import java.util.Date;
import java.util.List;

public class Orders {

private Integer id;

private Integer user_id;

private String number;

private Date createtime;

private String note;

//用户信息
private User user;

//订单明细
private List<Orderdetail> orderdetails;

public Integer getId() {
return id;
}

public void setId(Integer id) {
this.id = id;
}

public Integer getUserId() {
return user_id;
}

public void setUserId(Integer userId) {
this.user_id = userId;
}

public String getNumber() {
return number;
}

public void setNumber(String number) {
this.number = number;
}

public Date getCreatetime() {
return createtime;
}

public void setCreatetime(Date createtime) {
this.createtime = createtime;
}

public String getNote() {
return note;
}

public void setNote(String note) {
this.note = note;
}
public User getUser() {
return user;
}

public void setUser(User user) {
this.user = user;
}

public List<Orderdetail> getOrderdetailList() {
return orderdetails;
}

public void setOrderdetailList(List<Orderdetail> orderdetails) {
this.orderdetails = orderdetails;
}

@Override
public String toString() {
return "Orders [id=" + id + ", user_id=" + user_id + ", number="
+ number + ", createtime=" + createtime + ", note=" + note
+ ", user=" + user + ", orderdetails=" + orderdetails
+ "]";
}

}

订单明细实体

package com.hl.myabtis.first.beas;
/**
*  订单明细
* @author 浪丶荡
*
*/
public class Orderdetail {

private Integer id;

private Integer orders_id;

private Integer items_id;

private Integer items_number;

public Integer getId() {
return id;
}

public void setId(Integer id) {
this.id = id;
}

public Integer getOrders_id() {
return orders_id;
}

public void setOrders_id(Integer orders_id) {
this.orders_id = orders_id;
}

public Integer getItems_id() {
return items_id;
}

public void setItems_id(Integer items_id) {
this.items_id = items_id;
}

public Integer getItems_number() {
return items_number;
}

public void setItems_number(Integer items_number) {
this.items_number = items_number;
}

@Override
public String toString() {
return "Orderdetail [id=" + id + ", orders_id=" + orders_id
+ ", items_id=" + items_id + ", items_number=" + items_number
+ "]";
}

}

mapper映射文件

<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.hl.mybatis.first.mapper.OrdersCustomMapper">

<!-- 用户信息resultMap -->
<resultMap type="user" id="userResultMap">
<!-- 关联查询用户的唯一标识
column:指定唯一标识用户信息的列
javaType:映射到User的对应属性类型
-->
<id column="user_id" javaType="java.lang.Integer"/>
<result column="username" property="username"/>
<result column="sex" property="sex"/>
<result column="address" property="address"/>
</resultMap>
<!-- 配置Order映射信息
id：订餐结果集唯一标识
property：对应订单类属性
-->
<resultMap type="Orders" id="ordersResultMap">
<id column="orderId" property="id"/>
<result column="user_id" property="user_id"/>
<result column="number" property="number"/>
<result column="createtime" property="createtime"/>
<result column="note" property="note"/>
</resultMap>

<!-- 订单明细 resultMap-->
<resultMap type="com.hl.myabtis.first.beas.Orderdetail" id="ordersDetailResultMap">
<!-- 订单明细的唯一标识 -->
<id column="orderdetail_id" property="id"/>
<result column="itemsId" property="items_id"/>
<result column="itemsNum" property="items_number"/>
<result column="ordersID" property="orders_id"/>
</resultMap>

<!-- 定义查询订单关联查询用户ResultMap
com.hl.myabtis.first.beas.Orders将整个查询的信息映射到Order上
-->
<resultMap type="com.hl.myabtis.first.beas.Orders" id="ordersUserResultMap">
<!-- 配置Order映射信息
id：订餐结果集唯一标识
property：对应订单类属性
-->
<id column="orderId" property="id"/>
<result column="user_id" property="user_id"/>
<result column="number" property="number"/>
<result column="createtime" property="createtime"/>
<result column="note" property="note"/>

<association property="user" resultMap="userResultMap" />
</resultMap>

<!-- 查询订单及订单明细的resultMap -->
<resultMap type="com.hl.myabtis.first.beas.Orders" id="ordersAndOrderdetailResultMap" extends="ordersUserResultMap">
<!-- 订单以及用户信息通过继承获得 -->
<!-- 引用订单明细 resultMap-->
<collection property="orderdetails" resultMap="ordersDetailResultMap" />
</resultMap>

<!-- 查询订单关联 查询用户信息以及订单明细  ResultMap映射-->
<select id="findOrdersAndOrderdetailResultMap" resultMap="ordersAndOrderdetailResultMap">
SELECT
o.id as orderId,
o.note,
o.createtime,
o.number,
o.user_id,
u.address,
u.sex,
u.username,
od.id AS orderdetail_id,
od.items_id AS itemsId,
od.items_num AS itemsNum,
od.orders_id AS ordersID
FROM
USER u,
orders o,
orderdetail od
WHERE
o.user_id = u.id and o.id = od.orders_id
</select>
</mapper>

mapper接口

public interface OrdersCustomMapper {
//查询订单关联 查询用户信息以及订单明细  ResultMap映射
public List<Orders> findOrdersAndOrderdetailResultMap() throws Exception;

}

测试用例

package com.hl.mybatis.first.test;

import java.io.InputStream;
import java.util.List;

import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.Before;
import org.junit.Test;

import com.hl.myabtis.first.beas.Orders;
import com.hl.myabtis.first.beas.OrdersCustom;
import com.hl.mybatis.first.mapper.OrdersCustomMapper;

public class OrdersMapperTest {

private SqlSessionFactory sqlSessionFactory;

@Before
public void testBefore() throws Exception{

String resource = "SqlMapConfig.xml";
InputStream inputStream = Resources.getResourceAsStream(resource );
sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
}
@Test
public void testFindOrdersAndOrderdetailResultMap() throws Exception{
SqlSession sqlSession = sqlSessionFactory.openSession();
OrdersCustomMapper ordersMapper = sqlSession.getMapper(OrdersCustomMapper.class);
List<Orders> list = ordersMapper.findOrdersAndOrderdetailResultMap();
for (Orders order : list) {
System.out.println(order);
}
sqlSession.close();
}
}

附上源码：http://download.csdn.net/detail/leisure_life/9852850