java - 如何在mybatis select中编写select标签

Question

如果我有课

public class Product {
private int id; 
private String name;
private double price;
private String type;
}

dao 接口(interface)

public interface {
 public Product selectOne(int id);
}

数据库中的表

T_Product (
id tinyint,
name varchar(50),
price long,
type varchar(30) );

我想知道如何在mybatis中为selectOne方法编写sqlMapper!

Answer 1

这是注释的另一个选项:

public interface ProductMapper{
 @Select( "select id, name, price, tag from Product where id = #{id}" )
 public Product selectOne( @Param("id") int id);
}

这是xml中的另一种写法:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<mapper namespace="YOUR_INTERFACE_NAME_WITH_PACKAGE_NAME">
     <select id="selectOne" resultType="Product">
        select id, name, price, tag from Product where id = #{id}
    </select>
</mapper>

不需要结果映射，因为列可以直接映射到对象属性。