    @Test
    public void testGetMillSecond() {

        long result = DateUtil.getMillSecond("1584500160000");
        Assert.assertEquals(result, 1584500160000L);

        result = DateUtil.getMillSecond("1584500160000000");
        Assert.assertEquals(result, 1584500160000L);

        result = DateUtil.getMillSecond("1584500160000000000");
        Assert.assertEquals(result, 1584500160000L);

        long expect = 57600000; // 1970-01-02 00:00:00:000
        result = DateUtil.getMillSecond("1");
        Assert.assertEquals(result, expect);
    }