Calendar cal = Calendar.getInstance();
cal.setTime(new Date());
cal.add(Calendar.DAY_OF_YEAR, 1);
cal.set(Calendar.HOUR_OF_DAY, 7);
cal.set(Calendar.MINUTE, 0);
cal.set(Calendar.SECOND, 0);
System.out.println(cal.getTime());
原文：http://www.cnblogs.com/siashan/p/4273840.html