MyBatis——一对多

1、Java 实体

public class UserInfo {

    private Integer id;

    private String username;

    private List<OrderInfo> orderInfoList;

    public Integer getId() {
        return id;
    }

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

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public List<OrderInfo> getOrderInfoList() {
        return orderInfoList;
    }

    public void setOrderInfoList(List<OrderInfo> orderInfoList) {
        this.orderInfoList = orderInfoList;
    }

    @Override
    public String toString() {
        return "UserInfo{" +
                "id=" + id +
                ", username='" + username + '\'' +
                ", orderInfoList=" + orderInfoList +
                '}';
    }
}

public class OrderInfo {

    private Integer id;

    private Date ordertime;

    private Double total;

    private Integer uid;

    private UserInfo user;

    public Integer getId() {
        return id;
    }

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

    public Date getOrdertime() {
        return ordertime;
    }

    public void setOrdertime(Date ordertime) {
        this.ordertime = ordertime;
    }

    public Double getTotal() {
        return total;
    }

    public void setTotal(Double total) {
        this.total = total;
    }

    public Integer getUid() {
        return uid;
    }

    public void setUid(Integer uid) {
        this.uid = uid;
    }

    public UserInfo getUser() {
        return user;
    }

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

    @Override
    public String toString() {
        return "OrderInfo{" +
                "id=" + id +
                ", ordertime=" + ordertime +
                ", total=" + total +
                ", uid=" + uid +
                ", user=" + user +
                '}';
    }
}

2、mapper 文件

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.deppon.mapper.UserMapper">

    <resultMap id="userMap" type="com.deppon.domain.UserInfo">
        <result property="id" column="id"></result>
        <result property="username" column="username"></result>

        <collection property="orderInfoList" ofType="com.deppon.domain.OrderInfo">
            <result property="id" column="oid"></result>
            <result property="ordertime" column="ordertime"></result>
            <result property="total" column="total"></result>
        </collection>
    </resultMap>


    <select id="findAllUsers" resultMap="userMap">
        select u.*,o.id oid,o.ordertime,o.total,o.uid from user u left join orderinfo o on u.id = o.uid
    </select>

</mapper>

3、测试类

public class TestOrderMapperUtil {

    private OrderMapper orderMapper;

    private UserMapper userMapper;

    @Before
    public void before() throws IOException {
        String path = "SqlConfig.xml";
        InputStream inputStream = Resources.getResourceAsStream(path);
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        SqlSession session = sqlSessionFactory.openSession(true);
        orderMapper = session.getMapper(OrderMapper.class);
        userMapper = session.getMapper(UserMapper.class);
    }

    @Test
    public void test1(){
        List<OrderInfo> orderList = orderMapper.findOrderList();
        System.out.println(orderList);
    }

    @Test
    public void test2(){
        List<UserInfo> allUsers = userMapper.findAllUsers();
        System.out.println(allUsers);
    }
}