使用Calendar获取并修改时间

//获取当前时间Calendar cal = Calendar.getInstance();cal.add(Calendar.DAY_OF_YEAR, 3); //现在时间的3天后cal.set(Calendar.HOUR_OF_DAY, 8);cal.set(Calendar.MINUTE, 0);cal.set(Calendar.SECOND, 0);//MILLISECOND也要设为0， 否则写入数据库时会发生SECOND为1的情况cal.set(Calendar.MILLISECOND, 0);// 转换为DateDate date=cal.getTime();//转换为TimestampTimestamp expire = new Timestamp(date.getTime());