代码

package mncode.entity;

@Data
public class User {
    private Integer id;
    private String name;
    private Integer age;
    private String email;
    private String address;
}

mybatis-config.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"/>
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://localhost:3306/test"/>
                <property name="username" value="root"/>
                <property name="password" value="123456"/>
            </dataSource>
        </environment>
    </environments>
    <mappers>
        <mapper resource="UserMapper.xml"/>
    </mappers>
</configuration>

UserMapper.xml

<?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="mncode.mapper.UserMapper">
    <select id="queryById" resultType="mncode.entity.User">
        select * from User where id = #{id}
    </select>
</mapper>

package mncode.mapper;

public interface UserMapper {
    User queryById(Integer id);
}

示例1

    @Test
    public void test2() {
        String resource = "mybatis-config.xml";
        SqlSession sqlSession = null;
        try {
            InputStream inputStream = Resources.getResourceAsStream(resource);
            SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
            sqlSession = sqlSessionFactory.openSession();
            User user = sqlSession.selectOne("mncode.mapper.UserMapper.queryById",1);
            System.out.println(user);
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            sqlSession.close();
        }
    }

示例2

    @Test
    public void test3() {
        String resource = "mybatis-config.xml";
        SqlSession sqlSession = null;
        try {
            InputStream inputStream = Resources.getResourceAsStream(resource);
            SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
            sqlSession = sqlSessionFactory.openSession();
            UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
            User user = userMapper.queryById(1);
            System.out.println(user);
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            sqlSession.close();
        }
    }

示例3

使用注解方式：

public interface UserMapper {

    @Select("SELECT * FROM user WHERE id = #{id}")
    User queryById(Integer id);
}