Mybatis映射器

Posted 2021-01-17 大-雄

上一篇文章返回是resultType,但其无法定义多的属性，比如typeHandler,级联等。为了支持复杂映射，可以用resultMap属性，先定义resultmap属性：

<mapper namespace="com.ssm.chapter5.mapper.RoleMapper">
    <!-- 测试一级缓存  -->
    <!-- 
    <cache/>
     -->
    
    <resultMap id="roleMap" type="role">
        <id property="id" column="id" />
        <result property="roleName" column="role_name" />
        <result property="note" column="note" />
    </resultMap>

    <select id="getRoleUseResultMap" parameterType="long" resultMap="roleMap">
        select id, role_name, note from t_role where id = #{id}
    </select>

mapper:
    public Role getRoleUseResultMap(Long id);

test:
public static void testGetRoleUseResultMap() {
        SqlSession sqlSession = null;
        try {
            sqlSession = SqlSessionFactoryUtils.openSqlSession();
            RoleMapper roleMapper = sqlSession.getMapper(RoleMapper.class);
            Role role = roleMapper.getRoleUseResultMap(1L);
            System.out.println(role.getRoleName());
        } catch(Exception ex) {
            ex.printStackTrace();
        } finally {
            if (sqlSession != null) {
                sqlSession.close();
            }
        }
    }