mybatis(一对一配置 resultMap)

我不是女神ヾ 2022-07-12 01:22 171阅读 0赞

mybatis一对一配置：

需求：查询订单信息，并获取订单的用户信息

每个订单只能对应一个客户， 所以从订单到客户是一对一的关系。

user类（com.changez.sm.base.bean.User）所有属性：

private String id;
    	private String username;
    	private Date birthday;
    	private String sex;
    	private String address;

orders类（com.changez.sm.base.bean.Orders）所有属性：

private String id;
    	private String userId;
    	private String orderNum;
    	private Date createTime;
    	private String note;
    	private User user; //User对象

mapper.xml：

association：配置一对一中被包含对象属性

<resultMap type="com.changez.sm.base.bean.Orders" id="queryOrderAndUserResultMap">
    		<id column="ordersid" property="id"/>
    		<result column="user_id" property="userId"/>
    		<result column="order_num" property="orderNum"/>
    		<result column="create_time" property="createTime"/>
    		<result column="note" property="note"/>
    		
    		<association property="user" javaType="com.changez.sm.base.bean.User">
    			<id column="userid" property="id"/>
    			<result column="username" property="username"/>
    			<result column="birthday" property="birthday"/>
    			<result column="address" property="address"/>
    			<result column="sex" property="sex"/>
    		</association>
    	</resultMap>
    	<select id="queryOrderAndUser" resultMap="queryOrderAndUserResultMap">
    		
    		SELECT 
    			tco.id ordersid, tco.user_id, tco.order_num, tco.create_time, 
    			tcu.id userid, tcu.username, tcu.birthday, tcu.sex, tcu.address 
    		from 
    			temp_changez_orders tco,  temp_changez_user tcu 
    		WHERE 
    			tco.user_id=tcu.id
    	</select>