Date today = new Date();//獲取今天的日期
Calendar c = Calendar.getInstance();
c.setTime(today);
c.add(Calendar.DAY_OF_MONTH, 1);
Date tomorrow = c.getTime();//這是明天
c.setTime(today);
c.add(Calendar.DAY_OF_MONTH, -1);
Date yesterday = c.getTime();//這是昨天