public static long getPreMinuteMills(long rightnow) {
        return rightnow - (rightnow % MILLISECONDS_PER_MINUTE) - 1;
    }
@Test
    public void getPreMinuteMills() throws Exception {
        long now = System.currentTimeMillis();
        long pre = DateUtils.getPreMinuteMills(now);
        Assert.assertTrue(now - pre < 60000);
    }