Calendar、时间格式问题

Calendar初始化及设置相应时间参数

Calendar calendar = Calendar.getInstance();
calendar.set(Calendar.HOUR_OF_DAY,0);
calendar.set(Calendar.MINUTE,0);
calendar.set(Calendar.SECOND,0);
calendar.set(Calendar.MILLISECOND,0);

Calendar日期的增加减少

calendar.add(Calendar.DAY_OF_MONTH,1);

输出字符串HH与hh小时制不一样

SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss:SSS");
System.out.println("-------------------------------------------------------------------------");
System.out.println(simpleDateFormat.format(calendar.getTime()));