主要代码：

1 import java.text.DateFormat; 2 import java.text.SimpleDateFormat; 3 import java.util.Date; 4  5  6 public class TestDateTimeAdd 7 { 8  9     public static void main(String[] args)10     {11         try12         {13             subDateTime("2015-12-09 15:55:30", "2015-12-09 15:57:38");14         }15         catch (Exception e)16         {17             e.printStackTrace();18         }19     }20     21     22     public static void subDateTime(String beginTime,String endTime) throws Exception23     {24         25         /*26          * 时间转化样式27          */28         DateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");29         30         /*31          * 把字符类型的时间转化为标准时间样式32          */33         Date firstDateTimeDate = format.parse(beginTime);34         Date secondDateTimeDate = format.parse(endTime);35         36         /*37          * 得到时间的总毫秒数38          */39         long firstDateMilliSeconds = firstDateTimeDate.getTime();40         long secondDateMilliSeconds = secondDateTimeDate.getTime();41         42         /*43          * 两个日期相减44          */45         long subDateMilliSeconds = secondDateMilliSeconds - firstDateMilliSeconds;46         47         //毫秒转化为秒48         int totalSeconds = (int) (subDateMilliSeconds/1000);49         50         /*51          * 毫秒数转化为总天数52          */53 //        int days = totalSeconds / (3600*24);54         int days_remains = totalSeconds % (3600*24);55         56         /*57          * 天数转化为时58          */59         int hours = days_remains/3600;60         int hours_remains = days_remains % 3600;61         62         /*63          * 得到分钟数64          */65         int minutes = hours_remains / 60;66         67         /*68          * 得到秒数69          */70         int seconds = hours_remains % 60;71 72         String outTime = ((hours < 10) ? "0" : "") + hours + ":"+73                          ((minutes < 10) ? "0" : "") + minutes + ":" +74                          ((seconds < 10) ? "0" : "") + seconds;75          System.out.println(outTime);76     }77 }