pojo

private List<Orders> orders;

public class User implements Serializable {
	/**
	 * 
	 */
	private static final long serialVersionUID = 1L;
	private Integer id;
	private String username;
	private String sex;
	private Date birthday;
	private String address;

	private List<Orders> orders;

	
	
	public List<Orders> getOrders() {
		return orders;
	}
	public void setOrders(List<Orders> orders) {
		this.orders = orders;
	}
	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 String getSex() {
		return sex;
	}
	public void setSex(String 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;
	}
	@Override
	public String toString() {
		return "User [id=" + id + ", username=" + username + ", sex=" + sex
				+ ", birthday=" + birthday + ", address=" + address + "]";
	}

	
	

}

mapper.xml

	<resultMap type="com.it.mybatis.pojo.User" id="userOrderResultMap">
		<id property="id" column="id" />
		<result property="username" column="username" />
		<result property="birthday" column="birthday" />
		<result property="sex" column="sex" />
		<result property="address" column="address" />

		<!-- 配置一对多的关系 -->
		<collection property="orders" ofType="com.it.mybatis.pojo.Orders">
			<!-- 配置主键，是关联Order的唯一标识 -->
			<id property="id" column="oid" />
			<result property="number" column="number" />
			<result property="createtime" column="createtime" />
			<result property="note" column="note" />
		</collection>
	</resultMap>

	<!-- 一对多关联，查询订单同时查询该用户下的订单 -->
	<select id="queryUserOrder" resultMap="userOrderResultMap">
		SELECT
		u.id,
		u.username,
		u.birthday,
		u.sex,
		u.address,
		o.id oid,
		o.number,
		o.createtime,
		o.note
		FROM
		`user` u
		LEFT JOIN `orders` o ON u.id = o.user_id
	</select>