一篇文章弄懂Java8中的时间处理

        LocalDateTime localDateTime = LocalDateTime.of(1987, 4, 12, 1, 0, 0, 0);
        System.out.println(localDateTime);
        System.out.println(localDateTime.plusHours(1));

        ZonedDateTime zonedDateTime = ZonedDateTime.of(1987, 4, 12, 1, 0, 0, 0, ZoneId.systemDefault());
        System.out.println(zonedDateTime);
        System.out.println(zonedDateTime.plusHours(1));

        Instant instant = zonedDateTime.toInstant();
        ZonedDateTime zonedDateTime1 = instant.atZone(zonedDateTime.getZone());

        //ZonedDateTime 转  Instant
        Instant instant = ZonedDateTime.now().toInstant();

 
        //获取UTC毫秒数
        long epochMilli = instant.toEpochMilli();
        

        //Instant 转  ZonedDateTime
        ZonedDateTime zonedDateTime = instant.atZone(ZoneId.systemDefault());

        //字符串 转  ZonedDateTime
        ZonedDateTime zonedDateTime2 = ZonedDateTime.parse(zonedDateTime.toString());

        //基于UTC 偏移的毫秒数
        int totalSeconds = zonedDateTime.getOffset().getTotalSeconds();

        //Instant 转  LocalDateTime
        LocalDateTime localDateTime = LocalDateTime.ofInstant(instant, ZoneId.systemDefault());

        //LocalDateTime 转  ZonedDateTime
        ZonedDateTime zonedDateTime1 = localDateTime.atZone(ZoneId.systemDefault());


        ZoneRules zoneRules = ZoneId.systemDefault().getRules();

        //判断是否是夏令时时间
        boolean daylightSavings = zoneRules.isDaylightSavings(instant);


        Calendar calendar = Calendar.getInstance(TimeZone.getDefault());
        //Calendar 转 Instant
        Instant instant1 = calendar.toInstant();

        //Calendar  转   ZonedDateTime
        Calendar now = Calendar.getInstance();
        ZonedDateTime zdt = ZonedDateTime.ofInstant(now.toInstant(), ZoneId.systemDefault()));

        //Date 转 Instant
        Date date = new Date();
        Instant inst = date.toInstant();

        // Instant 转 Date
        Date newDate = Date.from(inst);

        //GreGorianCalendar 转 ZonedDateTime
        GregorianCalendar cal = GregorianCalendar.from(ZonedDateTime.now());
        TimeZone tz = cal.getTimeZone();
        ZonedDateTime zdt1 = cal.toZonedDateTime();
        
        //ZonedDateTime 转 GregorianCalendar
        GregorianCalendar newCal = GregorianCalendar.from(zdt1);

        LocalDateTime ldt = zdt.toLocalDateTime();
        LocalDate date2 = zdt.toLocalDate();
        LocalTime time2 = zdt.toLocalTime();