Joda-Time开源库

Joda-Time是一个面向 Java™ 平台的易于使用的开源时间日期库。

依赖

 <dependency>
     <groupId>joda-time</groupId>
     <artifactId>joda-time</artifactId>
     <version>2.9.9</version>
 </dependency>

用法

1.时间日期类生成

 //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  

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(); 

3.星期的处理

 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;
 }  

4.与JDK对象转换

 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()); 

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);  

6.时间比较

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); 

7.时间差

 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"));  

8.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"); 

Joda-Time的Util模板

 public class DateTimeUtil {
     public static final String STANDARD_FORMAT = "yyyy-MM-dd HH:mm:ss";

     public static Date strToDate(String dateTimeStr){
         DateTimeFormatter dateTimeFormatter = DateTimeFormat.forPattern(STANDARD_FORMAT);
         DateTime dateTime = dateTimeFormatter.parseDateTime(dateTimeStr);
         return dateTime.toDate();
     }

     public static String dateToStr(Date date){
         if (date == null){
             return StringUtils.EMPTY;
         }
         DateTime dateTime = new DateTime(date);
         return dateTime.toString(STANDARD_FORMAT);
     }
 }

参考：https://www.ibm.com/developerworks/cn/java/j-jodatime.html