订单：

public class Order{private int id;private Date ordertime;private User user;private int total;

<?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.dao.OrderMapper"><resultMap id="orderMap" type="order"><!--数据表字段        实体类属性--><id column="OrderID" property="id"></id><result column="ordertime" property="ordertime"/><result column="total" property="total"/><!--一对一的方式  两种--><!--<result column="UserID" property="user.id"/>--><!--<result column="name" property="user.name"/>--><!--<result column="password" property="user.password"/>--><!--实体类属性名称   实体类（order）属性的类型       --><association property="user" javaType="user"><id column="UserID" property="id"/><result column="name" property="name"/><result column="password" property="password"/></association></resultMap><!--查询完毕后将结果封装到orderMap里--><select id="findAll" resultMap="orderMap">select *,o.uid as UserID ,o.id as OrderID from user as u inner join orders as o on o.uid=u.id order by u.id</select></mapper>

用户：

public class User {private int id;private String name;private String password;private List<Order> orderList;

<?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.dao.UserMapper">
<resultMap id="userMap" type="user"><id column="UserID" property="id"/><result column="name" property="name"/><result column="password" property="password"/><!-- 实体类属性中的集合名称        集合中的数据类型--><collection property="orderList" ofType="order"><id column="OrderID" property="id"/><result column="total" property="total"/><result column="ordertime" property="ordertime"/></collection>
</resultMap><select id="findAll" resultMap="userMap">select * , u.id as UserID ,o.id as OrderID from user as u inner join orders as o on o.uid=u.id order by UserID
</select></mapper>

订单的Mapper查询结果为一对一，主要是在Order里如何配置一个User对象
用户的Mapper查询结果为一对多，主要是在User里如何配置一个Order的集合