public static String getPrintSize(long size) {
        DecimalFormat df = new DecimalFormat("#.00");
        if (size < KB_SIZE) {
            return size + "B";
        } else if (size < MB_SIZE) {
            return df.format((double) size / KB_SIZE) + "KB";
        } else if (size < GB_SIZE) {
            return df.format((double) size / MB_SIZE) + "MB";
        } else {
            return df.format((double) size / GB_SIZE) + "GB";
        }
    }
@Test
    public void assertGetPrintSize() {
        Assert.isTrue(Objects.equals(ByteConvertUtil.getPrintSize(220), "220B"));
        Assert.isTrue(Objects.equals(ByteConvertUtil.getPrintSize(2200), "2.15KB"));
        Assert.isTrue(Objects.equals(ByteConvertUtil.getPrintSize(2200000), "2.10MB"));
        Assert.isTrue(Objects.equals(ByteConvertUtil.getPrintSize(2200000000L), "2.05GB"));
    }