MyBatis笔记04 - 解决字段名与实体类属性名不相同的冲突

5. 解决字段名与实体类属性名不相同的冲突



5.1. 准备表和数据：

CREATE TABLE orders(
order_id INT PRIMARY KEY AUTO_INCREMENT,
order_no VARCHAR(20),
order_price FLOAT
);
INSERT INTO orders(order_no, order_price) VALUES('aaaa', 23);
INSERT INTO orders(order_no, order_price) VALUES('bbbb', 33);
INSERT INTO orders(order_no, order_price) VALUES('cccc', 22);

5.2. 定义实体类：

public class Order {
private int id;
private String orderNo;
private float price;
//生成set和get方法
......
}

5.3. 实现getOrderById(id)的查询：

方式一: 通过在sql语句中定义别名

<select id="selectOrder" parameterType="int" resultType="_Order">
select order_id id, order_no orderNo,order_price price from orders where order_id=#{id}
</select>

方式二: 通过<resultMap>

<select id="selectOrderResultMap" parameterType="int" resultMap="orderResultMap">
select * from orders where order_id=#{id}
</select>

<resultMap type="_Order" id="orderResultMap">
<id property="id" column="order_id"/>
<result property="orderNo" column="order_no"/>
<result property="price" column="order_price"/>
</resultMap>