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LocalDateTime与字符串互转/Date互转/LocalDate互转/指定日期/时间比较

作者:互联网

转载   https://www.cnblogs.com/jpfss/p/10413985.html

 

Java 8中表示日期和时间的类有多个,主要的有:

与字符串互转

简单粗暴

        DateTimeFormatter df = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");
	LocalDateTime time = LocalDateTime.now();
	String localTime = df.format(time);

LocalDateTime ldt = LocalDateTime.parse("2018-06-01 10:12:05",df); System.out.println("LocalDateTime转成String类型的时间:"+localTime); System.out.println("String类型的时间转成LocalDateTime:"+ldt);
 

与Date互转

  java.util.Date date = new java.util.Date();
    Instant instant = date.toInstant();
    ZoneId zone = ZoneId.systemDefault();
    LocalDateTime localDateTime = LocalDateTime.ofInstant(instant, zone);

  LocalDateTime localDateTime = LocalDateTime.now();
    ZoneId zone = ZoneId.systemDefault();
    Instant instant = localDateTime.atZone(zone).toInstant();
    java.util.Date date = Date.from(instant);
 

与LocalDate互转

  LocalDateTime now = LocalDateTime.now();
  LocalDate localDate = now.toLocalDate();
 
  ocalDate localDate = LocalDate.now();
    ZoneId zone = ZoneId.systemDefault();
    Instant instant = localDate.atStartOfDay().atZone(zone).toInstant();
    java.util.Date date = Date.from(instant);

与时间戳互转

  long time = new Date().getTime();
  System.out.println("java时间戳:" + time);
  DateTimeFormatter dateTimeFormatter3 = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");
  Instant instant = Instant.ofEpochMilli(time);
  ZoneId zoneId = ZoneId.systemDefault();
  LocalDateTime localDateTime1 = LocalDateTime.ofInstant(instant, zoneId);
  System.out.println("时间戳转LocalDateTime:" + localDateTime1.format(dateTimeFormatter3));

        
  LocalDateTime localDateTime2 = LocalDateTime.now();
  ZoneId zoneId1 = ZoneId.systemDefault();
  Instant instant1 = localDateTime2.atZone(zoneId1).toInstant();
  System.out.println("LocalDateTime转时间戳:" + instant1.toEpochMilli());
 

调整时间

 

  LocalDateTime now = LocalDateTime.now();
	//明天
  LocalDateTime plusDays = now.plusDays(1);
	//昨天
  LocalDateTime plusDays2 = now.plusDays(-1);
	//还有时分等同理
 

时间比较

 

  LocalDateTime now = LocalDateTime.now();
  Long epochMilli = now.atZone(ZoneId.systemDefault()).toInstant().toEpochMilli();
 

  然后比较long就可以了,默认时区是ZoneId.systemDefault()

  //北京时区
  ZoneId bjZone = ZoneId.of("GMT+08:00")
 

间隔计算

使用Duration进行 day,hour,minute,second等的计算 

使用Period进行Year,Month的计算

Duration duration = Duration.between(localDateTime,localDateTime4);
duration.toDays();
duration.toHours();
duration.toMinutes();
Period period2 = Period.between(localDateTime.toLocalDate(),localDateTime4.toLocalDate());
period2.getYears();
period2.getMonths();
period2.toTotalMonths();
 

 

判断是否是今天或昨天

    String time = "2018-08-09 11:20:45";
        DateTimeFormatter dtf = DateTimeFormatter.ofPattern("uuuu-MM-dd HH:mm:ss");
        LocalDateTime localTime = LocalDateTime.parse(time, dtf);
        LocalDateTime startTime = LocalDate.now().atTime(0, 0, 0);
        LocalDateTime endTime = LocalDate.now().atTime(23, 59, 59);
        LocalDateTime startYesterday = LocalDate.now().plusDays(-1).atTime(0, 0, 0);
        LocalDateTime endYesterday = LocalDate.now().plusDays(-1).atTime(23, 59, 59);
 
        //如果小于昨天的开始日期
        if (localTime.isBefore(startYesterday)) {
            System.out.println("时间是过去");
        }
        //时间是昨天
        if (localTime.isAfter(startYesterday) && localTime.isBefore(endYesterday)) {
            System.out.println("时间是昨天");
        }
        //如果大于今天的开始日期,小于今天的结束日期
        if (localTime.isAfter(startTime) && localTime.isBefore(endTime)) {
            System.out.println("时间是今天");
        }
        //如果大于今天的结束日期
        if (localTime.isAfter(endTime)) {
            System.out.println("时间是未来");
        }

标签:System,ZoneId,Date,LocalDateTime,互转,println,now,out
来源: https://www.cnblogs.com/Cate-Hunter/p/15841689.html