詳解Java8版本中的新特性 線程安全日期類

Tue Sep 10 09:34:04 CST 2019

private StringBuffer format(Date date, StringBuffer toAppendTo,
                              FieldDelegate delegate) {
        // Convert input date to time field list
        calendar.setTime(date);
 
        boolean useDateFormatSymbols = useDateFormatSymbols();
 
        for (int i = 0; i < compiledPattern.length; ) {
            int tag = compiledPattern[i] >>> 8;
            int count = compiledPattern[i++] & 0xff;
            if (count == 255) {
                count = compiledPattern[i++] << 16;
                count |= compiledPattern[i++];
            }
 
            switch (tag) {
            case TAG_QUOTE_ASCII_CHAR:
                toAppendTo.append((char)count);
                break;
 
            case TAG_QUOTE_CHARS:
                toAppendTo.append(compiledPattern, i, count);
                i += count;
                break;
 
            default:
                subFormat(tag, count, delegate, toAppendTo, useDateFormatSymbols);
                break;
            }
        }
        return toAppendTo;
    }

//獲取當(dāng)前年月日
        LocalDate localDate = LocalDate.now();
        //構(gòu)造指定的年月日
        LocalDate localDate1 = LocalDate.of(2019, 9, 10);

        //獲取年、月、日、星期幾
        int year = localDate.getYear();
        int year1 = localDate.get(ChronoField.YEAR);
        Month month = localDate.getMonth();
        int month1 = localDate.get(ChronoField.MONTH_OF_YEAR);
        int day = localDate.getDayOfMonth();
        int day1 = localDate.get(ChronoField.DAY_OF_MONTH);
        DayOfWeek dayOfWeek = localDate.getDayOfWeek();
        int dayOfWeek1 = localDate.get(ChronoField.DAY_OF_WEEK);

//創(chuàng)建LocalTime
        LocalTime localTime = LocalTime.of(13, 51, 10);
        LocalTime localTime1 = LocalTime.now();

        //獲取小時(shí)
        int hour = localTime.getHour();
        int hour1 = localTime.get(ChronoField.HOUR_OF_DAY);
        //獲取分
        int minute = localTime.getMinute();
        int minute1 = localTime.get(ChronoField.MINUTE_OF_HOUR);
        //獲取秒
        int second = localTime.getSecond();
        int second1 = localTime.get(ChronoField.SECOND_OF_MINUTE);

//創(chuàng)建對(duì)象
        LocalDateTime localDateTime = LocalDateTime.now();
        LocalDateTime localDateTime1 = LocalDateTime.of(2019, Month.SEPTEMBER, 10, 14, 46, 56);
        //LocalDate+LocalTime-->LocalDateTime
        LocalDateTime localDateTime2 = LocalDateTime.of(localDate, localTime);
        LocalDateTime localDateTime3 = localDate.atTime(localTime);
        LocalDateTime localDateTime4 = localTime.atDate(localDate);

        //獲取LocalDate
        LocalDate localDate2 = localDateTime.toLocalDate();
        //獲取LocalTime
        LocalTime localTime2 = localDateTime.toLocalTime();

// 默認(rèn)時(shí)區(qū)
ZonedDateTime zbj = ZonedDateTime.now(); 
// 用指定時(shí)區(qū)獲取當(dāng)前時(shí)間
ZonedDateTime zny = ZonedDateTime.now(ZoneId.of("America/New_York")); 

LocalDateTime ldt = LocalDateTime.of(2019, 9, 15, 15, 16, 17);
ZonedDateTime zbj = ldt.atZone(ZoneId.systemDefault());
ZonedDateTime zny = ldt.atZone(ZoneId.of("America/New_York"));

ZonedDateTime zbj = ZonedDateTime.now(ZoneId.of("Asia/Shanghai"));
// 轉(zhuǎn)換為紐約時(shí)間:
ZonedDateTime zny = zbj.withZoneSameInstant(ZoneId.of("America/New_York"));

ZonedDateTime zdt = ...
LocalDateTime ldt = zdt.toLocalDateTime();

//創(chuàng)建Instant對(duì)象
        Instant instant = Instant.now();
        //獲取秒數(shù)
        long currentSecond = instant.getEpochSecond();
        //獲取毫秒數(shù)
        long currentMilli = instant.toEpochMilli();
        long l = System.currentTimeMillis();

//修改LocalDate、LocalTime、LocalDateTime、Instant
        LocalDateTime localDateTime = LocalDateTime.of(2019, Month.SEPTEMBER, 10,
                14, 46, 56);
        //增加一年
        localDateTime = localDateTime.plusYears(1);
        localDateTime = localDateTime.plus(1, ChronoUnit.YEARS);
        //減少一個(gè)月
        localDateTime = localDateTime.minusMonths(1);
        localDateTime = localDateTime.minus(1, ChronoUnit.MONTHS);

		//通過with修改某些值
        //修改年為2020
        localDateTime = localDateTime.withYear(2020);
        //修改為2022
        localDateTime = localDateTime.with(ChronoField.YEAR, 2022);
		//還可以修改月、日

LocalDate localDate = LocalDate.now();
LocalDate localDate1 = localDate.with(TemporalAdjusters.firstDayOfYear());

LocalDate localDate = LocalDate.of(2019, 9, 10);
String s1 = localDate.format(DateTimeFormatter.BASIC_ISO_DATE);
String s2 = localDate.format(DateTimeFormatter.ISO_LOCAL_DATE);
//自定義格式化
DateTimeFormatter dateTimeFormatter = DateTimeFormatter.ofPattern("dd/MM/yyyy");
String s3 = localDate.format(dateTimeFormatter);

LocalDate localDate1 = LocalDate.parse("20190910", DateTimeFormatter.BASIC_ISO_DATE);
LocalDate localDate2 = LocalDate.parse("2019-09-10", DateTimeFormatter.ISO_LOCAL_DATE);

//構(gòu)造器1：傳入格式字符串
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");

//構(gòu)造器2：傳入格式字符串和地區(qū)
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("E, yyyy-MMMM-dd HH:mm:ss", Locale.US);
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("E, yyyy-MMMM-dd HH:mm:ss", Locale.CHINA);