<?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="com.sea.crm.mapper.OrderMapper">
	<!-- 使用as 給列取別名解決類名和屬性名不一致的情況 -->
	<!--<select id="queryAll" resultType="Order"> SELECT id,user_id as userId,number,createtime,note 
		FROM orders </select> -->
	<!-- 使用resultMap解決列名和屬性名不一致的情況 -->
	<!-- 配置一個resultMap映射列和屬性 -->
	<resultMap type="Order" id="orderMap">
		<!-- id：設(shè)置ResultMap的id -->
		<!-- 定義主鍵 ,非常重要。如果是多個字段,則定義多個id -->
		<!-- property：主鍵在pojo中的屬性名 -->
		<!-- column：主鍵在數(shù)據(jù)庫中的列名 -->
		<id column="id" property="id" />
		<!-- 映射其他普通列 -->
		<result column="user_id" property="userId" />
		<result property="number" column="number" />
		<result property="createtime" column="createtime" />
</resultMap>
	<!-- 方法的返回值可以使用 -->
	<select id="queryAll" resultMap="orderMap">
		SELECT id,user_id ,number,createtime,note FROM orders
	</select>
</mapper>

public class OrderMapperTest {
	
		SqlSessionFactory factory = null;
		private OrderMapper orderMapper = null;
		@Before
		public void testInit() {
			// 1. 創(chuàng)建SqlSessionFactoryBuilder對象
			SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
			// 2. 加載SqlMapConfig.xml配置文件
			// /20181013_mybatis/config/SqlMapConfig.xml
			InputStream in = MyBatisTest.class.getResourceAsStream("/SqlMapConfig.xml");
			// 3. 創(chuàng)建SqlSessionFactory對象
			factory = builder.build(in);
		}
        @Test
		public void testqueryAll() {
			SqlSession session = factory.openSession();
			OrderMapper orderMapper = session.getMapper(OrderMapper.class);
			List<Order> orders = orderMapper.queryAll();
			System.out.println(orders);
		}
	}

    <select id="getUser" parameterType="String"
        resultType="User">
        select * from user where username=#{username}
    </select>

    <select id="getOrder" parameterType="int"
        resultType="Order">
        select order_id  id,order_name orderName from orders where order_id=#{id}
    </select>

    <!-- 配置一個映射關(guān)系 -->
    <resultMap type="Order" id="orderResultMap">
        <id property="id" column="order_id"/>
        <result property="orderName" column="order_name"/>
    </resultMap>
    <!-- 查詢結(jié)果集引用配好的映射關(guān)系 -->
    <select id="getOrder" parameterType="int"
        resultMap="orderResultMap">
        select order_id ,order_name from orders where order_id=#{id}
    </select>