<?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">
<!-- namespace：命名空间，用于隔离sql，还有一个很重要的作用，后面会讲 -->
<mapper namespace="com.yuanqinnan.mapper.UserMapper">
    <select id="queryUserById" parameterType="int" resultType="com.yuanqinnan.model.User">
    SELECT * FROM `user`where id=#{id}
   </select>
    <!-- 查询 user 表的所有数据-->
    <select id="selectUserAll" resultType="com.yuanqinnan.model.User">
        select * from user
    </select>
    <!--
            1、${value}里面必须要写value，不然会报错
            2、${}表示拼接 sql 字符串，将接收到的参数不加任何修饰拼接在sql语句中
            3、使用${}会造成 sql 注入
    -->
    <select id="selectLikeUserName" resultType="com.yuanqinnan.model.User" parameterType="String">
        select * from user where username like '%${value}%'
    </select>
    <!--#{}实现-->
    <select id="selectLikeUserName2" resultType="com.yuanqinnan.model.User" parameterType="String">
        select * from user where username like #{username}
    </select>
    <!-- 向 user 表插入一条数据 -->
    <insert id="insertUser" parameterType="com.yuanqinnan.model.User">
        insert into user(id,username,sex,birthday,address)
            value(#{id},#{username},#{sex},#{birthday},#{address})
    </insert>
    <!-- 保存用户 -->
    <insert id="saveUser" parameterType="com.yuanqinnan.model.User">
        <!-- selectKey 标签实现主键返回 -->
        <!-- keyColumn:主键对应的表中的哪一列 -->
        <!-- keyProperty：主键对应的pojo中的哪一个属性 -->
        <!-- order：设置在执行insert语句前执行查询id的sql，在执行insert语句之后执行查询id的sql -->
        <!-- resultType：设置返回的id的类型 -->
        <selectKey keyColumn="id" keyProperty="id" order="AFTER"
                   resultType="int">
            SELECT LAST_INSERT_ID()
        </selectKey>
        INSERT INTO `user`
        (username,birthday,sex,address) VALUES
        (#{username},#{birthday},#{sex},#{address})
    </insert>
    <!-- 根据 id 更新 user 表的数据 -->
    <update id="updateUserById" parameterType="com.yuanqinnan.model.User">
        update user set username=#{username} where id=#{id}
    </update>

    <!-- 根据 id 删除 user 表的数据 -->
    <delete id="deleteUserById" parameterType="int">
        delete from user where id=#{id}
    </delete>
</mapper>

public interface UserMapper {

    //查询用户
    User queryUserById(int id);
    //查询用户列表
    List<User> selectUserAll();

    //模糊查询
    List<User> selectLikeUserName(String username);

    //新增
    void saveUser(User user);
    
}

<mappers>
    <!-- 映射文件方式1，一个一个的配置-->
    <mapper resource="config/sqlmap/User.xml"/>
    <mapper resource="config/mapper/UserMapper.xml"/>
</mappers>

public class MapperTest {
    private SqlSessionFactory sqlSessionFactory;

    @Before
    public void init() throws Exception {
        // 创建SqlSessionFactoryBuilder
        SqlSessionFactoryBuilder sqlSessionFactoryBuilder = new SqlSessionFactoryBuilder();
        // 加载SqlMapConfig.xml配置文件
        InputStream inputStream = Resources.getResourceAsStream("config/SqlMapConfig.xml");
        // 创建SqlsessionFactory
        this.sqlSessionFactory = sqlSessionFactoryBuilder.build(inputStream);
    }

    @Test
    public void testQueryUserById() {
        // 获取sqlSession，和spring整合后由spring管理
        SqlSession sqlSession = this.sqlSessionFactory.openSession();

        // 从sqlSession中获取Mapper接口的代理对象
        UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
        // 执行查询方法
        User user = userMapper.queryUserById(1);
        System.out.println(user);

        // 和spring整合后由spring管理
        sqlSession.close();
    }

    @Test
    public void testQueryUserByUsername() {
        // 获取sqlSession，和spring整合后由spring管理
        SqlSession sqlSession = this.sqlSessionFactory.openSession();

        // 从sqlSession中获取Mapper接口的代理对象
        UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
        // 执行查询方法
        List<User> list = userMapper.selectLikeUserName("张");
        for (User user : list) {
            System.out.println(user);
        }

        // 和spring整合后由spring管理
        sqlSession.close();
    }

    @Test
    public void testSaveUser() {
        // 获取sqlSession，和spring整合后由spring管理
        SqlSession sqlSession = this.sqlSessionFactory.openSession();

        // 从sqlSession中获取Mapper接口的代理对象
        UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
        // 创建保存对象
        User user = new User();
        user.setUsername("刘备");
        user.setBirthday(new Date());
        user.setSex("1");
        user.setAddress("蜀国");
        // 执行查询方法
        userMapper.saveUser(user);
        System.out.println(user);


        // 和spring整合后由spring管理
        sqlSession.commit();
        sqlSession.close();
    }
}