public static long fileName2Offset(final String fileName) {
        return Long.parseLong(fileName.substring(fileName.length() - 20));
    }
@Test
    public void fileName2OffsetTest() {
        Assert.assertEquals(0, MessageStoreUtil.fileName2Offset("cfcd208400000000000000000000"));
        Assert.assertEquals(4294937144L, MessageStoreUtil.fileName2Offset("b10da56800000000004294937144"));
    }