Java日期比较大小的3种方式示例详解

String today= new SimpleDateFormat("yyyy-MM-dd hh:mm:ss").format(new Date());

String startDate="2020-11-13 00:00:00";
//当前时间endDate 是2020-11-14 09:52:41
String endDate= new SimpleDateFormat("yyyy-MM-dd hh:mm:ss").format(new Date());
// return 1
System.out.println(endDate.compareTo(startDate));

String startDate="2020-11-13 00:00:00";
String endDate= "2020-11-14 23:59:59";
SimpleDateFormat simpleDateFormat=new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");
try{
    Date date01=simpleDateFormat.parse(startDate);
    Date date02=simpleDateFormat.parse(endDate);
    // 精确到毫秒
    long milliSecond01=date01.getTime();
    long milliSecond02=date02.getTime();
    // true
    System.out.println(milliSecond02 > milliSecond01);
}catch (Exception e){
}

String startDate="2020-11-13 00:00:00";
String endDate= "2020-11-14 23:59:59";
SimpleDateFormat simpleDateFormat=new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");
try{
    Date date01=simpleDateFormat.parse(startDate);
    Date date02=simpleDateFormat.parse(endDate);
    // true , 11-13号 在 11-14号 之前 
       System.out.println(date01.before(date02));
}catch (Exception e){
}

//获取日历实例
Calendar calendar=Calendar.getInstance();
Date date=calendar.getTime();

Calendar calendar=Calendar.getInstance();
int year=calendar.get(Calendar.YEAR);
int month=calendar.get(Calendar.MONTH)+1;
int day=calendar.get(Calendar.DATE);
int hour=calendar.get(Calendar.HOUR_OF_DAY);
int minute=calendar.get(Calendar.MINUTE);
int second=calendar.get(Calendar.SECOND);
System.out.println("当前时间："+year+"年 "+month+"月 "+day+"日 "+hour+"时 "+minute+"分 "+second+"秒");