java 8 提供的 时间api java.time 比原来的Calendar 方便很多。主要提供了
日期类：LocalDate 时间类：LocateDateTime 时间戳操作类：Instant 时间持续时间计算：Duration 时区：ZoneId 日期间隔：Period java 8 api 是整合了原第三方工具(org.joda.time)，使用将会更加方便。以下实例针对，日常使用的时间计算方式，进行实例验证。可以根据自己需要提取，时间工具类。
以下是具体的使用实例，建议大家都转换新的时间方式，虽然中间可能要花费些时间，但个人感觉还是值得。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("下个月的今天:" + 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("本月最后1天的日期: " + localDate.with(TemporalAdjusters.lastDayOfMonth())); System.out.println("本年最后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("今天是本周的第:" + localDate.getDayOfWeek().getValue() + "天"); // before System.out.println("今天在20171001日之前：" + localDate.isBefore(LocalDate.of(2017, 10, 1))); // 格式化 System.out.println("格式化：" + localDate.format(DateTimeFormatter.ofPattern("yyyy-MM-dd"))); // Instant 时间戳转换 System.out.println("当前时间:" + Instant.now().atZone(ZoneId.systemDefault())); System.out.println("当前的时间戳：" + Instant.now().toEpochMilli()); System.out.println( "时间戳转为时间字符串：" + 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(); // 计算两个时间，之间的长度 持续运行时间 Duration duration = Duration.between(first, second); System.out.println("程序运行时间：" + duration); // 日期间隔计算 Period period = localDate.until(localDate.with(TemporalAdjusters.lastDayOfYear())); System.out.println("Period Format= " + period); System.out.println("Months remaining in the year= " + period.getMonths()); }