Mybatis培训教程

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;

}

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>

 

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