public static List<String> findPlaceholder(String sql) {
        Matcher matcher = pattern.matcher(sql);
        List<String> list = new ArrayList<>();
        while (matcher.find()) {
            list.add(matcher.group());
        }
        return list;
    }
@Test
    void m1() {
        List<String> list = SqlUtils.findPlaceholder("select {@table},{@table:t},{@table:t:r} from table");
        assertThat(list).contains("{@table}", "{@table:t}", "{@table:t:r}");
    }