<mapper namespace="com.oracle.dao.one2manyDao">

    <resultMap type="com.oracle.pojo.Order" id="orderResuleMap">

        <id column="orderId" property="id"/>

        <result column="ordered_date" property="ordered_date"/>

        <result column="shipped_date" property="shipped_date"/>

        <result column="total" property="total"/>

        <collection property="orderlines" ofType="com.oracle.pojo.OrderLine" javaType="java.util.HashSet" column="order_id">

            <id column="id" property="id"/>

            <result column="price" property="price"/>

            <result column="quantity" property="quantity"/>

            <result column="product" property="product"/>

        </collection>

    </resultMap>

    <select id="getOrderAndOrderLines" resultMap="orderResuleMap" parameterType="java.lang.Long">

        select o.id as orderId,o.ordered_date,o.shipped_date,o.total,

        ol.id,ol.price,ol.quantity, ol.product

        from t_order o left join t_orderline ol

        on o.id=ol.order_id

        where o.id=#{id}

    </select>

</mapper>

//实体类

public class OrderLine implements Serializable {

    private long id;

    private double price;

    private long quantity;

    private String product;

    private Order order;

public class Order implements Serializable {

    private Long id;

    private Date ordered_date;

    private Date shipped_date;

    private Long total;

    private Set<OrderLine> orderlines = new HashSet<OrderLine>();