获取当天年月日，及开始结束时间

Calendar calendar=Calendar.getInstance();
System.out.println("年："+calendar.get(Calendar.YEAR));
System.out.println("月："+(calendar.get(Calendar.MONTH)+1));
System.out.println("日："+calendar.get(Calendar.DATE));
calendar.set(Calendar.MILLISECOND,0);
calendar.set(Calendar.SECOND,0);
calendar.set(Calendar.MINUTE,0);
calendar.set(Calendar.HOUR_OF_DAY,0);
System.out.println(DateFormatUtils.format(calendar.getTime(),"yyyy-MM-dd HH:mm:ss"));
calendar.set(Calendar.HOUR_OF_DAY,24);
System.out.println(DateFormatUtils.format(calendar.getTime(),"yyyy-MM-dd HH:mm:ss"));