java中的DateTime的使用

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引入org.joda.time.DateTime

<dependency>
   <groupId>joda-time</groupId>
   <artifactId>joda-time</artifactId>
   <version>2.9.8</version>
</dependency>

1.初始化时间

DateTime time = new DateTime(2018,4,23,23, 7,18,888);
// 2018年4月23日23点7分18秒888毫秒  

2.按格式输出时间(将DateTime格式转换为字符串)

 String time = dateTime.toString("yyyy-MM-dd hh:mm:ss.SSSa");

小写hh是12小时制,大写HH是24小时制

3.将字符串转换为DateTime格式

 DateTimeFormatter format = DateTimeFormat .forPattern("yyyy-MM-dd HH:mm:ss");  
                   
 DateTime dateTime = DateTime.parse("2018-4-23 23:12:16", format); 

4.取得当前时间

DateTime time= new DateTime();

5.计算两个日期间隔的天数

 LocalDate start=new LocalDate(2018,4,23);    
 LocalDate end=new LocalDate(2019, 06, 16);    
 int days = Days.daysBetween(start, end).getDays(); 

6.增加日期

      DateTime dateTime = DateTime.parse("2018-04-23");  
                dateTime = dateTime1.plusDays(1);  
                dateTime = dateTime1.plusHours(2);  
                dateTime = dateTime1.plusMinutes(3);  
                dateTime = dateTime1.plusMonths(4);  
                dateTime = dateTime1.plusSeconds(5);  
                dateTime = dateTime1.plusWeeks(6);  
                dateTime = dateTime1.plusYears(7);  

7.减少日期

  DateTime dateTime = DateTime.parse("2018-04-23");  
                dateTime = dateTime1.minusMillis(1);  
                dateTime = dateTime1.minusHours(1);  
                dateTime = dateTime1.minusSeconds(1);;  

8.判断是否闰月

DateTime time = new DateTime();    
 org.joda.time.DateTime.Property month = time.monthOfYear();    
  System.out.println("是否闰月:" + month.isLeap());  

9.DateTime与Date转换

DateTime time = new DateTime(new Date());    
 Date date = time.toDate();    
 DateTime time2 = new DateTime(System.currentTimeMillis());    
 time2.getMillis();  

10.DateTime与Calendar转换

Calendar calendar = Calendar.getInstance();    
 dateTime = new DateTime(calendar);