查找Java中的天差

使用浮动，我看到了问题。使用时间戳似乎不是找到两个日期之间的天差的好方法。

11至11 = 0.0
11至12 = 1.0
11至13 = 2.0
11至14 = 3.0
11至15 = 3.9583333
11至16 = 4.9583335
11至17 = 5.9583335
11至18 = 6.9583335
11至19 = 7.9583335

展望未来，我发现确定日期差异的最确定的方法是

Calendar cre_calendar = new GregorianCalendar((2013), (1), 11);        Calendar exp_calendar = new GregorianCalendar((2013), (1), 19);        Calendar maxDays = new GregorianCalendar(((2013)), (12), 31);        if (exp_calendar.get(Calendar.DAY_OF_YEAR) < cre_calendar     .get(Calendar.DAY_OF_YEAR)) { System.out         .println((exp_calendar.get(Calendar.DAY_OF_YEAR) + maxDays      .get(Calendar.DAY_OF_YEAR))      - cre_calendar.get(Calendar.DAY_OF_YEAR));        } else { System.out.println((exp_calendar.get(Calendar.DAY_OF_YEAR))         - cre_calendar.get(Calendar.DAY_OF_YEAR));        }