DATE与Calendar

        //日期类 类之后是对象
		Date date=new Date();
		System.out.println(date);
		//获得年 year 1900-当前时间差
		System.out.println(date.getYear());
		//获得月 month 0-11代表1-12
		System.out.println(date.getMonth());
		//获得日 date
		System.out.println(date.getDate());
		//获得时 hours
		System.out.println(date.getHours());
		//获得分 minutes
		System.out.println(date.getMinutes());
		//获得秒 seconds
		System.out.println(date.getSeconds());
		//获得星期 day
		System.out.println(date.getDay());
		//获得毫秒 time 1970-当前时间毫秒值
		System.out.println(date.getTime());
       

       //循环某个东西一千次需要多久
		Date date1 = new Date();
		long time1 =date1.getTime();
	    for(int h=0;h<1000;h++) {
			System.out.println(h);
		}
		Date date3 =new Date();
		long time2 =date3.getTime();
	    System.out.println(time2-time1);
	    //出生到现在经历了多少天 
	    long a=date2.getTime();
	    long b=date.getTime();
	    long c=b-a;
	    System.out.println(c/1000/60/60/24);

        //把date类转成String类 日期格式化
		SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd");
		String aString = dateFormat.format(date);
		System.out.println(aString);
				
		//把String类解析date类
		String bir="2000-01-31";
		Date date2 = dateFormat.parse(bir);
		System.out.println(date2.getDay());
		System.out.println(date2.getDate());
		System.out.println(date2.getTime());
		System.out.println(System.currentTimeMillis());
  
        //日历类 
        //不需要new 直接调取方法
        Calendar calendar = Calendar.getInstance();
        System.out.println(calendar);
		//获取年		System.out.println(calendar.get(calendar.YEAR)+"年");
		//获取月		System.out.println((calendar.get(calendar.MONTH)+1)+"月");
		//获取日		System.out.println(calendar.get(calendar.DAY_OF_MONTH)+"日");
		//获取时		System.out.println(calendar.get(calendar.HOUR_OF_DAY)+"时");
		//获取分		System.out.println(calendar.get(calendar.MINUTE)+"分");
		//获取秒		System.out.println(calendar.get(calendar.SECOND)+"秒");