@Override
    public User findUserByUsername(String username) {
        String sql = "SELECT username,password FROM users WHERE username=? ";
        try {
            return this.jt.queryForObject(sql, new Object[] {username}, USER_ROW_MAPPER);
        } catch (CannotGetJdbcConnectionException e) {
            LogUtil.FATAL_LOG.error("[db-error] " + e.toString(), e);
            throw e;
        } catch (EmptyResultDataAccessException e) {
            return null;
        } catch (Exception e) {
            LogUtil.FATAL_LOG.error("[db-other-error]" + e.getMessage(), e);
            throw new RuntimeException(e);
        }
    }
@Test
    void testFindUserByUsername() {
        User username = externalUserPersistService.findUserByUsername("username");
        
        assertNull(username);
    }