public static Map<String, String> toStringMap(Map<String, Object> param) {
        Map<String, String> covertMap = new HashMap<>();
        if (CollectionUtils.isNotEmpty(param)) {
            param.forEach((key, value) -> {
                if (value != null) {
                    if (value instanceof CharSequence || value instanceof Character) {
                        covertMap.put(key, value.toString());
                    } else {
                        covertMap.put(key, StringUtils.toString(value));
                    }
                }
            });
        }
        return covertMap;
    }
@Test
    public void testObjectMapToStringMap() {
        Map<String, Object> objMap = new HashMap<>();
        Date now = new Date(123);
        objMap.put("a", "aa");
        objMap.put("b", 22);
        objMap.put("c", now);
        Map<String, String> strMap = CollectionUtils.toStringMap(objMap);
        Assertions.assertEquals("aa", strMap.get("a"));
        Assertions.assertEquals("22", strMap.get("b"));
        Assertions.assertEquals(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS").format(now), strMap.get("c"));
    }