@Test
public void dateToStr() throws Exception {

    long s1 = 1501127802975l; // 2017-07-27 11:56:42:975 +8
    long s2 = 1501127835658l; // 2017-07-27 11:57:15:658 +8
    TimeZone timeZone = TimeZone.getDefault();
    Date date0 = new Date(0 - timeZone.getOffset(0));
    Date date1 = new Date(s1 - timeZone.getOffset(s1));
    Date date2 = new Date(s2 - timeZone.getOffset(s2));
    Assert.assertEquals(DateUtils.dateToStr(date0), "1970-01-01 00:00:00");
    Assert.assertEquals(DateUtils.dateToStr(date1), "2017-07-27 03:56:42");
    Assert.assertEquals(DateUtils.dateToStr(date2), "2017-07-27 03:57:15");
}