Java 8 新特性：Java 类库的新特性之日期时间API (Date/Time API )

Date date = new Date(2016,1,1);   
System.out.println(date); 

Calendar calendar = Calendar.getInstance();   
calendar.set(2016, 5, 2);

public class Test {
  public static void main(String[] args) {
    Calendar birth = Calendar.getInstance();
    birth.set(1975, Calendar.MAY, 26);
    Calendar now = Calendar.getInstance();
    System.out.println(daysBetween(birth, now)); // 输出结果为14963，值不固定
    System.out.println(daysBetween(birth, now)); // 输出结果 显示 0？
  }
}
  public static long daysBetween(Calendar begin, Calendar end) {   
       long daysBetween = 0;   
       while(begin.before(end)) {   
           begin.add(Calendar.DAY_OF_MONTH, 1);   
           daysBetween++;   
      }   
      return daysBetween;   
  } 
}

public static long daysBetween(Calendar begin, Calendar end) {   
  Calendar calendar = (Calendar) begin.clone(); // 复制   
      long daysBetween = 0;   
      while(calendar.before(end)) {   
          calendar.add(Calendar.DAY_OF_MONTH, 1);   
          daysBetween++;   
      }   
      return daysBetween;      
} 

//Clock 时钟
      Clock clock1 = Clock.systemDefaultZone();//获取系统默认时区 (当前瞬时时间 )
      System.out.println( "系统时间日期："+clock1.instant() );
      System.out.println( "时间毫秒："+clock1.millis() );
      final Clock clock = Clock.systemUTC();//获取系统时钟，并将其转换成使用UTC时区的日期和时间
      System.out.println( "时间日期："+clock.instant() );
      System.out.println( "时间毫秒值："+clock.millis() );

Instant instant = clock1.instant();
      Date javadate = Date.from(instant); 
      System.out.println( "date："+javadate);

    // 输出所有可见的时区ID，eg：Asia/Aden, America/Cuiaba, Etc/GMT+9等
    System.out.println(ZoneId.getAvailableZoneIds());
    ZoneId zone1 = ZoneId.of("Europe/Berlin");
    ZoneId zone2 = ZoneId.of("Brazil/East");
    System.out.println(zone1.getRules());
    System.out.println(zone2.getRules());
    //输出结果： ZoneRules[currentStandardOffset=+01:00]
    //输出结果： ZoneRules[currentStandardOffset=-03:00]

// Get the local date and local time
      final LocalTime time = LocalTime.now();
      final LocalTime timeFromClock = LocalTime.now( clock );
      System.out.println( time );
      System.out.println( timeFromClock );

ZoneId zone1 = ZoneId.of("Europe/Berlin");
    ZoneId zone2 = ZoneId.of("Brazil/East");
    LocalTime now1 = LocalTime.now(zone1);
    LocalTime now2 = LocalTime.now(zone2);
    System.out.println("时区：Europe/Berlin---"+now1); 
    System.out.println("时区：Brazil/East---"+now2); 

LocalTime late = LocalTime.of(22, 12, 18);//时分秒
    System.out.println(late); // 输出结果：22:12:18
    DateTimeFormatter germanFormatter = DateTimeFormatter.ofLocalizedTime(FormatStyle.SHORT)
        .withLocale(Locale.GERMAN);
    LocalTime leetTime = LocalTime.parse("15:39", germanFormatter);
    System.out.println(leetTime); // 输出结果： 15:39

Clock clock = Clock.systemDefaultZone();// 获取系统默认时区 (当前瞬时时间 )
    // Get the local date and local time
    final LocalDate date = LocalDate.now();
    final LocalDate dateFromClock = LocalDate.now(clock);
    System.out.println(date);
    System.out.println(dateFromClock);

    DateTimeFormatter germanFormatter = DateTimeFormatter.ofLocalizedDate(FormatStyle.MEDIUM)
        .withLocale(Locale.GERMAN);
    LocalDate xmas = LocalDate.parse("25.10.2016", germanFormatter);
    System.out.println(xmas);

Clock clock = Clock.systemDefaultZone();// 获取系统默认时区 (当前瞬时时间 )
    // Get the local date/time
    final LocalDateTime datetime = LocalDateTime.now();
    final LocalDateTime datetimeFromClock = LocalDateTime.now(clock);
    System.out.println(datetime);
    System.out.println(datetimeFromClock);

  LocalDateTime sylvester = LocalDateTime.of(2016, Month.DECEMBER, 31, 23, 59, 59);
    DayOfWeek dayOfWeek = sylvester.getDayOfWeek();
    System.out.println(dayOfWeek);      
    Month month = sylvester.getMonth();
    System.out.println(month);        
    long minuteOfDay = sylvester.getLong(ChronoField.MINUTE_OF_DAY);
    System.out.println(minuteOfDay);  

LocalDateTime sylvester = LocalDateTime.of(2016, Month.DECEMBER, 31, 23, 59, 59);
    Instant instant = sylvester
            .atZone(ZoneId.systemDefault())
            .toInstant();
    Date legacyDate = Date.from(instant);
    System.out.println(legacyDate);

  DateTimeFormatter formatter = DateTimeFormatter.ofPattern("MM dd, yyyy - HH:mm");
    LocalDateTime parsed = LocalDateTime.parse("05 03, 2016 - 07:13", formatter);
    String string = formatter.format(parsed);
    System.out.println(string);

    Clock clock = Clock.systemDefaultZone();// 获取系统默认时区 (当前瞬时时间 )
    // Get the zoned date/time
    final ZonedDateTime zonedDatetime = ZonedDateTime.now();
    final ZonedDateTime zonedDatetimeFromClock = ZonedDateTime.now(clock);
    final ZonedDateTime zonedDatetimeFromZone = ZonedDateTime.now(ZoneId.of("America/Los_Angeles"));
    System.out.println(zonedDatetime);
    System.out.println(zonedDatetimeFromClock);
    System.out.println(zonedDatetimeFromZone);

                // Get duration between two dates
    final LocalDateTime from = LocalDateTime.of(2014, Month.APRIL, 16, 0, 0, 0);//年月日时分秒
    final LocalDateTime to = LocalDateTime.of(2015, Month.APRIL, 16, 23, 59, 59);
    final Duration duration = Duration.between(from, to);
    System.out.println("Duration in days: " + duration.toDays());
    System.out.println("Duration in hours: " + duration.toHours());</span>

ZoneId zone1 = ZoneId.of("America/Cuiaba");
     ZoneId zone2 = ZoneId.of("Brazil/East");
     LocalTime now1 = LocalTime.now(zone1);
     LocalTime now2 = LocalTime.now(zone2);
     long hoursBetween = ChronoUnit.HOURS.between(now1, now2);
     long minutesBetween = ChronoUnit.MINUTES.between(now1, now2);
     System.out.println(hoursBetween); // 1
     System.out.println(minutesBetween); // 60