life = 91
today = System.currentTimeMillis()
expireDate = new Date(today + life * 24 * 3600 * 1000);
new Date(today)
Wed Nov 28 15:21:01 GMT+05:30 2012
按预期返回今天的日期
为什么new Date(expireDate)
返回Tue Nov 20 05:17:16 GMT+05:30 2012
早于今天的日期,而我实际上期望提前一个日期?