Java日期计算之Joda-Time

Joda-Time提供了一组Java类包用于处理包括ISO8601标准在内的date和time。可以利用它把JDK Date和Calendar类完全替换掉，而且仍然能够提供很好的集成。

http://joda-time.sourceforge.net/

版本：joda-time-2.1.jar

1、时间类得作成

//方法一：取系统点间
 DateTime dt1 = new DateTime();

 //方法二：通过java.util.Date对象生成
 DateTime dt2 = new DateTime(new Date());

 //方法三：指定年月日点分秒生成(参数依次是：年,月,日,时,分,秒,毫秒)
 DateTime dt3 = new DateTime(2012, 5, 20, 13, 14, 0, 0);

 //方法四：ISO8601形式生成
 DateTime dt4 = new DateTime("2012-05-20");
 DateTime dt5 = new DateTime("2012-05-20T13:14:00");

 //只需要年月日的时候
 LocalDate localDate = new LocalDate(2009, 9, 6);// September 6, 2009

 //只需要时分秒毫秒的时候
 LocalTime localTime = new LocalTime(13, 30, 26, 0);// 1:30:26PM

//方法一：取系统点间
DateTime dt1 = new DateTime();

//方法二：通过java.util.Date对象生成
DateTime dt2 = new DateTime(new Date());

//方法三：指定年月日点分秒生成(参数依次是：年,月,日,时,分,秒,毫秒)
DateTime dt3 = new DateTime(2012, 5, 20, 13, 14, 0, 0);

//方法四：ISO8601形式生成
DateTime dt4 = new DateTime("2012-05-20");
DateTime dt5 = new DateTime("2012-05-20T13:14:00");

//只需要年月日的时候
LocalDate localDate = new LocalDate(2009, 9, 6);// September 6, 2009

//只需要时分秒毫秒的时候
LocalTime localTime = new LocalTime(13, 30, 26, 0);// 1:30:26PM

2、获取年月日点分秒

DateTime dt = new DateTime();
 //年
 int year = dt.getYear();
 //月
 int month = dt.getMonthOfYear();
 //日
 int day = dt.getDayOfMonth();
 //星期
 int week = dt.getDayOfWeek();
 //点
 int hour = dt.getHourOfDay();
 //分
 int min = dt.getMinuteOfHour();
 //秒
 int sec = dt.getSecondOfMinute();
 //毫秒
 int msec = dt.getMillisOfSecond();

DateTime dt = new DateTime();
//年
int year = dt.getYear();
//月
int month = dt.getMonthOfYear();
//日
int day = dt.getDayOfMonth();
//星期
int week = dt.getDayOfWeek();
//点
int hour = dt.getHourOfDay();
//分
int min = dt.getMinuteOfHour();
//秒
int sec = dt.getSecondOfMinute();
//毫秒
int msec = dt.getMillisOfSecond();

3、星期的特殊处理

DateTime dt = new DateTime();

 //星期
 switch(dt.getDayOfWeek()) {
 case DateTimeConstants.SUNDAY:
     System.out.println("星期日");
     break;
 case DateTimeConstants.MONDAY:
     System.out.println("星期一");
     break;
 case DateTimeConstants.TUESDAY:
     System.out.println("星期二");
     break;
 case DateTimeConstants.WEDNESDAY:
     System.out.println("星期三");
     break;
 case DateTimeConstants.THURSDAY:
     System.out.println("星期四");
     break;
 case DateTimeConstants.FRIDAY:
     System.out.println("星期五");
     break;
 case DateTimeConstants.SATURDAY:
     System.out.println("星期六");
     break;
}

DateTime dt = new DateTime();

//星期
switch(dt.getDayOfWeek()) {
case DateTimeConstants.SUNDAY:
	System.out.println("星期日");
	break;
case DateTimeConstants.MONDAY:
	System.out.println("星期一");
	break;
case DateTimeConstants.TUESDAY:
	System.out.println("星期二");
	break;
case DateTimeConstants.WEDNESDAY:
	System.out.println("星期三");
	break;
case DateTimeConstants.THURSDAY:
	System.out.println("星期四");
	break;
case DateTimeConstants.FRIDAY:
	System.out.println("星期五");
	break;
case DateTimeConstants.SATURDAY:
	System.out.println("星期六");
	break;
}

4、与JDK日期对象的转换

DateTime dt = new DateTime();

 //转换成java.util.Date对象
 Date d1 = new Date(dt.getMillis());
Date d2 = dt.toDate();

 //转换成java.util.Calendar对象
Calendar c1 = Calendar.getInstance();
c1.setTimeInMillis(dt.getMillis());
Calendar c2 = dt.toCalendar(Locale.getDefault());

DateTime dt = new DateTime();

//转换成java.util.Date对象
Date d1 = new Date(dt.getMillis());
Date d2 = dt.toDate();

//转换成java.util.Calendar对象
Calendar c1 = Calendar.getInstance();
c1.setTimeInMillis(dt.getMillis());
Calendar c2 = dt.toCalendar(Locale.getDefault());

5、日期前后推算

DateTime dt = new DateTime();

 //昨天
 DateTime yesterday = dt.minusDays(1);
 //明天
 DateTime tomorrow = dt.plusDays(1);
 //1个月前
 DateTime before1month = dt.minusMonths(1);
 //3个月后
 DateTime after3month = dt.plusMonths(3);
 //2年前
 DateTime before2year = dt.minusYears(2);
 //5年后
 DateTime after5year = dt.plusYears(5);

DateTime dt = new DateTime();

//昨天
DateTime yesterday = dt.minusDays(1);		
//明天
DateTime tomorrow = dt.plusDays(1);		
//1个月前
DateTime before1month = dt.minusMonths(1);		
//3个月后
DateTime after3month = dt.plusMonths(3);		
//2年前
DateTime before2year = dt.minusYears(2);		
//5年后
DateTime after5year = dt.plusYears(5);

6、取特殊日期

DateTime dt = new DateTime();

 //月末日期
DateTime lastday = dt.dayOfMonth().withMaximumValue();

 //90天后那周的周一
 DateTime firstday = dt.plusDays(90).dayOfWeek().withMinimumValue();

DateTime dt = new DateTime();	

//月末日期	
DateTime lastday = dt.dayOfMonth().withMaximumValue();

//90天后那周的周一
DateTime firstday = dt.plusDays(90).dayOfWeek().withMinimumValue();

7、时区

//默认设置为日本时间
 DateTimeZone.setDefault(DateTimeZone.forID("Asia/Tokyo"));
 DateTime dt1 = new DateTime();

 //伦敦时间
 DateTime dt2 = new DateTime(DateTimeZone.forID("Europe/London"));

//默认设置为日本时间
DateTimeZone.setDefault(DateTimeZone.forID("Asia/Tokyo"));
DateTime dt1 = new DateTime();

//伦敦时间
DateTime dt2 = new DateTime(DateTimeZone.forID("Europe/London"));

8、计算区间

DateTime begin = new DateTime("2012-02-01");
 DateTime end = new DateTime("2012-05-01");

 //计算区间毫秒数
 Duration d = new Duration(begin, end);
 long time = d.getMillis();

 //计算区间天数
 Period p = new Period(begin, end, PeriodType.days());
 int days = p.getDays();

 //计算特定日期是否在该区间内
 Interval i = new Interval(begin, end);
 boolean contained = i.contains(new DateTime("2012-03-01"));

DateTime begin = new DateTime("2012-02-01");
DateTime end = new DateTime("2012-05-01");

//计算区间毫秒数
Duration d = new Duration(begin, end);
long time = d.getMillis();

//计算区间天数
Period p = new Period(begin, end, PeriodType.days());
int days = p.getDays();

//计算特定日期是否在该区间内
Interval i = new Interval(begin, end);
boolean contained = i.contains(new DateTime("2012-03-01"));

9、日期比较

DateTime d1 = new DateTime("2012-02-01");
 DateTime d2 = new DateTime("2012-05-01");

 //和系统时间比
 boolean b1 = d1.isAfterNow();
 boolean b2 = d1.isBeforeNow();
 boolean b3 = d1.isEqualNow();

 //和其他日期比
 boolean f1 = d1.isAfter(d2);
 boolean f2 = d1.isBefore(d2);
 boolean f3 = d1.isEqual(d2);

DateTime d1 = new DateTime("2012-02-01");
DateTime d2 = new DateTime("2012-05-01");

//和系统时间比
boolean b1 = d1.isAfterNow();
boolean b2 = d1.isBeforeNow();
boolean b3 = d1.isEqualNow();

//和其他日期比
boolean f1 = d1.isAfter(d2);
boolean f2 = d1.isBefore(d2);
boolean f3 = d1.isEqual(d2);

10、格式化输出

DateTime dateTime = new DateTime();

 String s1 = dateTime.toString("yyyy/MM/dd hh:mm:ss.SSSa");
 String s2 = dateTime.toString("yyyy-MM-dd HH:mm:ss");
 String s3 = dateTime.toString("EEEE dd MMMM, yyyy HH:mm:ssa");
 String s4 = dateTime.toString("yyyy/MM/dd HH:mm ZZZZ");
 String s5 = dateTime.toString("yyyy/MM/dd HH:mm Z");

DateTime dateTime = new DateTime();

String s1 = dateTime.toString("yyyy/MM/dd hh:mm:ss.SSSa");
String s2 = dateTime.toString("yyyy-MM-dd HH:mm:ss");
String s3 = dateTime.toString("EEEE dd MMMM, yyyy HH:mm:ssa");
String s4 = dateTime.toString("yyyy/MM/dd HH:mm ZZZZ");
String s5 = dateTime.toString("yyyy/MM/dd HH:mm Z");

参考资料：http://www.ibm.com/developerworks/cn/java/j-jodatime.html

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