### Question:
UserDao { public UserDO selectByUsername(String username) { return template.queryForObject("SELECT id, username, password, create_time FROM users WHERE username = ? LIMIT 1", new BeanPropertyRowMapper<>(UserDO.class), username); }  int insert(UserDO entity); int insert0(UserDO entity); int updateById(UserDO entity); int deleteById(Integer id); UserDO selectById(Integer id); UserDO selectByUsername(String username); List<UserDO> selectByIds(List<Integer> ids);  }### Answer:
@Test public void testSelectByUsername() { UserDO user = userDao.selectByUsername("yunai"); System.out.println(user); }