java 8 新特性 時間api使用實例

java 8 提供的 時間api java.time 比原來的Calendar 方便不少。主要提供了
日期類：LocalDate
時間類：LocateDateTime
時間戳操做類：Instant
時間持續時間計算：Duration
時區：ZoneId
日期間隔：Period
java 8 api 是整合了原第三方工具(org.joda.time)，使用將會更加方便。

如下實例針對，平常使用的時間計算方式，進行實例驗證。能夠根據本身須要提取，時間工具類。
如下是具體的使用實例，建議你們都轉換新的時間方式，雖然中間可能要花費些時間，但我的感受仍是值得。

public static void main(String[] args) {
		Instant first = Instant.now();
		// Current Time
		LocalTime time = LocalTime.now();
		System.out.println("Current Time=" + time);
		// Creating LocalTime by providing input arguments
		LocalTime specificTime = LocalTime.of(12, 20, 25, 40);
		System.out.println("Specific Time of Day=" + specificTime);
		// Try creating time by providing invalid inputs
		// Current date in "Asia/Kolkata", you can get it from ZoneId javadoc
		LocalTime timeKolkata = LocalTime.now(ZoneId.of("Asia/Kolkata"));
		System.out.println("Current Time in IST=" + timeKolkata);

		// Getting date from the base date i.e 01/01/1970
		LocalTime specificSecondTime = LocalTime.ofSecondOfDay(10000);
		System.out.println("10000th second time= " + specificSecondTime);
		// 今日
		LocalDate localDate = LocalDate.now();
		System.out.println("今日日期:" + localDate);
		// Create
		LocalDate firstDay_2017 = LocalDate.of(2017, Month.JANUARY, 1);
		System.out.println("Specific Date=" + firstDay_2017);
		LocalDate hundredDay2017 = LocalDate.ofYearDay(2017, 200);
		System.out.println("200th day of 2017=" + hundredDay2017);
		// plus and minus operations
		System.out.println("昨天日期: " + localDate.minusDays(1));
		System.out.println("明天日期: " + localDate.plusDays(1));
		System.out.println("上月的今天：" + localDate.minusMonths(1));
		System.out.println("下個月的今天:" + localDate.plusMonths(1));
		// Temporal adjusters for adjusting the dates
		System.out.println("本月第1天的日期: " + localDate.with(TemporalAdjusters.firstDayOfMonth()));
		System.out.println("本月最後1天的日期: " + localDate.with(TemporalAdjusters.lastDayOfMonth()));
		System.out.println("本年最後1天的日期: " + localDate.with(TemporalAdjusters.lastDayOfYear()));
		// TemporalFieldfor adjusting the dates
		System.out.println("今天是：" + localDate.getYear() + "第" + localDate.get(ChronoField.ALIGNED_WEEK_OF_YEAR) + "周");
		System.out.println("今天是周: " + localDate.getDayOfWeek());
		System.out.println("今天是本週的第:" + localDate.getDayOfWeek().getValue() + "天");
		// before
		System.out.println("今天在20171001日以前：" + localDate.isBefore(LocalDate.of(2017, 10, 1)));
		// 格式化
		System.out.println("格式化：" + localDate.format(DateTimeFormatter.ofPattern("yyyy-MM-dd")));
		// Instant 時間戳轉換
		System.out.println("當前時間:" + Instant.now().atZone(ZoneId.systemDefault()));
		System.out.println("當前的時間戳：" + Instant.now().toEpochMilli());
		System.out.println(
				"時間戳轉爲時間字符串：" + Instant.ofEpochMilli(Instant.now().toEpochMilli()).atZone(ZoneId.systemDefault()));
		// Locale date time
		// Current Date
		LocalDateTime today = LocalDateTime.now();
		System.out.println("Current DateTime=" + today);

		// Current Date using LocalDate and LocalTime
		today = LocalDateTime.of(LocalDate.now(), LocalTime.now());
		System.out.println("Current DateTime=" + today);

		// Creating LocalDateTime by providing input arguments
		LocalDateTime specificDate = LocalDateTime.of(2014, Month.JANUARY, 1, 10, 10, 30);
		System.out.println("Specific Date=" + specificDate);

		// Current date in "Asia/Kolkata", you can get it from ZoneId javadoc
		LocalDateTime todayKolkata = LocalDateTime.now(ZoneId.of("Asia/Kolkata"));
		System.out.println("Current Date in IST=" + todayKolkata);

		// Getting date from the base date i.e 01/01/1970
		LocalDateTime dateFromBase = LocalDateTime.ofEpochSecond(10000, 0, ZoneOffset.UTC);
		System.out.println("10000th second time from 01/01/1970= " + dateFromBase);

		// Duration example
		Duration thirtyDay = Duration.ofDays(30);
		System.out.println("30天" + thirtyDay);

		// wait some time while something happens
		Instant second = Instant.now();
		// 計算兩個時間，之間的長度 持續運行時間
		Duration duration = Duration.between(first, second);
		System.out.println("程序運行時間：" + duration);
		// 日期間隔計算
		Period period = localDate.until(localDate.with(TemporalAdjusters.lastDayOfYear()));
		System.out.println("Period Format= " + period);
		System.out.println("Months remaining in the year= " + period.getMonths());
	}