【MyBatis】学习笔记07：模糊查询

/**
     * 根据用户名模糊查询
     * @param username 用户名的关键字
     * @return  List<User> 用户列表
     */
    List<User> getUserByLike(@Param("username") String username);

<!--    List<User> getUserByLike(@Param("username") String username);-->
    <select id="getUserByLike" resultType="User">
         select * from t_users where userName like "%${username}%"
    </select>

@Test
    public void testGetUserByLike(){
        SqlSession sqlSession = SqlSessionUtils.getSqlSession();
        SQLMapper mapper = sqlSession.getMapper(SQLMapper.class);
        List<User> list = mapper.getUserByLike("三");
        System.out.println(list);
    }

[User{userId='5',userName='张三'userCount='mllt@xrilang.com',userPassword='123'userGrade='0',userRegDate='null'userBlance='0'}, User{userId='6',userName='李三'userCount='xirlang@mllt.c',userPassword='124'userGrade='0',userRegDate='null'userBlance='0'}]

<!--    List<User> getUserByLike(@Param("username") String username);-->
    <select id="getUserByLike" resultType="User">
         <!-- select * from t_users where userName like "%${username}%"-->
        select * from t_users where userName like concat("%",#{username},"%")
    </select>
<!--concat 拼接-->

[User{userId='5',userName='张三'userCount='mllt@xrilang.com',userPassword='123'userGrade='0',userRegDate='null'userBlance='0'}, User{userId='6',userName='李三'userCount='xirlang@mllt.c',userPassword='124'userGrade='0',userRegDate='null'userBlance='0'}]

<!--    List<User> getUserByLike(@Param("username") String username);-->
    <select id="getUserByLike" resultType="User">
         <!-- select * from t_users where userName like "%${username}%"-->
         <!-- select * from t_users where userName like concat("%",#{username},"%")-->
        select * from t_users where userName like "%"#{username}"%"
</select>

[User{userId='5',userName='张三'userCount='mllt@xrilang.com',userPassword='123'userGrade='0',userRegDate='null'userBlance='0'}, User{userId='6',userName='李三'userCount='xirlang@mllt.c',userPassword='124'userGrade='0',userRegDate='null'userBlance='0'}]