Java8 Date调整时间用法

古城微笑少年丶 2022-09-06 00:28 259阅读 0赞

Java8 Date调整时间用法

Date mydate=new Date();
    String mydateStr=mydate.toInstant().atZone(ZoneId.systemDefault())
    .toLocalDate().minusDays(1)
    .format(DateTimeFormatter.ofPattern("yyyyMMdd"));

下面是几个常用的用法

// 01. java.util.Date --> java.time.LocalDateTime
    public void UDateToLocalDateTime() { 
        java.util.Date date = new java.util.Date();
        Instant instant = date.toInstant();
        ZoneId zone = ZoneId.systemDefault();
        LocalDateTime localDateTime = LocalDateTime.ofInstant(instant, zone);
    }
    
    // 02. java.util.Date --> java.time.LocalDate
    public void UDateToLocalDate() { 
        java.util.Date date = new java.util.Date();
        Instant instant = date.toInstant();
        ZoneId zone = ZoneId.systemDefault();
        LocalDateTime localDateTime = LocalDateTime.ofInstant(instant, zone);
        LocalDate localDate = localDateTime.toLocalDate();
    }
    
    // 03. java.util.Date --> java.time.LocalTime
    public void UDateToLocalTime() { 
        java.util.Date date = new java.util.Date();
        Instant instant = date.toInstant();
        ZoneId zone = ZoneId.systemDefault();
        LocalDateTime localDateTime = LocalDateTime.ofInstant(instant, zone);
        LocalTime localTime = localDateTime.toLocalTime();
    }
    // 04. java.time.LocalDateTime --> java.util.Date
    public void LocalDateTimeToUdate() { 
        LocalDateTime localDateTime = LocalDateTime.now();
        ZoneId zone = ZoneId.systemDefault();
        Instant instant = localDateTime.atZone(zone).toInstant();
        java.util.Date date = Date.from(instant);
    }
    // 05. java.time.LocalDate --> java.util.Date
    public void LocalDateToUdate() { 
        LocalDate localDate = LocalDate.now();
        ZoneId zone = ZoneId.systemDefault();
        Instant instant = localDate.atStartOfDay().atZone(zone).toInstant();
        java.util.Date date = Date.from(instant);
    }
    
    // 06. java.time.LocalTime --> java.util.Date
    public void LocalTimeToUdate() { 
        LocalTime localTime = LocalTime.now();
        LocalDate localDate = LocalDate.now();
        LocalDateTime localDateTime = LocalDateTime.of(localDate, localTime);
        ZoneId zone = ZoneId.systemDefault();
        Instant instant = localDateTime.atZone(zone).toInstant();
        java.util.Date date = Date.from(instant);
    }
    
    //另外一个用法
    	Calendar cal = Calendar.getInstance();
    	cal.setTime(new Date());
    	cal.add(Calendar.DAY_OF_MONTH, -1); //include current day
    	cal.set(cal.get(Calendar.YEAR), cal.get(Calendar.MONTH), cal.get(Calendar.DAY_OF_MONTH), 0, 0, 0);
    	Date fromDate = cal.getTime();
    	cal.set(cal.get(Calendar.YEAR), cal.get(Calendar.MONTH), cal.get(Calendar.DAY_OF_MONTH), 23, 59, 59);
        Date toDate = cal.getTime();

参考文档

1.  Date常用方法和相互时间调整。见[这里的文章][Link 1]

[Link 1]: https://blog.csdn.net/weixin_39626745/article/details/114351270