java 任意两个时间差，天数，小时数，分钟数，秒数

在java 编程中，不可避免用到计算时间差。前面我写过几篇文章，关于java 时间计算的，还有timezone 转换的文章，但没有这么具体到相差到天数，小时，分钟，秒数都列出来的情况，所以这里再总结下。
1. 用JDK 自带API 实现。
2.利用 joda time library 来实现.

首先看看用JDK 自带API 是如何实现的。

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
 
public class DateTimeUtils {
 
	public static void main(String[] args) {
 
	  DateTimeUtils obj = new DateTimeUtils();
	  SimpleDateFormat simpleDateFormat = 
                new SimpleDateFormat("dd/M/yyyy hh:mm:ss");
 
	  try {
 
		Date date1 = simpleDateFormat.parse("10/10/2013 11:30:10");
		Date date2 = simpleDateFormat.parse("13/10/2013 20:35:55");
 
		obj.printDifference(date1, date2);
 
	  } catch (ParseException e) {
		e.printStackTrace();
	  }
 
	}
 
	//1 minute = 60 seconds
	//1 hour = 60 x 60 = 3600
	//1 day = 3600 x 24 = 86400
	public void printDifference(Date startDate, Date endDate){
 
		//milliseconds
		long different = endDate.getTime() - startDate.getTime();
 
		System.out.println("startDate : " + startDate);
		System.out.println("endDate : "+ endDate);
		System.out.println("different : " + different);
 
		long secondsInMilli = 1000;
		long minutesInMilli = secondsInMilli * 60;
		long hoursInMilli = minutesInMilli * 60;
		long daysInMilli = hoursInMilli * 24;
 
		long elapsedDays = different / daysInMilli;
		different = different % daysInMilli;
 
		long elapsedHours = different / hoursInMilli;
		different = different % hoursInMilli;
 
		long elapsedMinutes = different / minutesInMilli;
		different = different % minutesInMilli;
 
		long elapsedSeconds = different / secondsInMilli;
 
		System.out.printf(
		    "%d days, %d hours, %d minutes, %d seconds%n", 
		    elapsedDays,
		    elapsedHours, elapsedMinutes, elapsedSeconds);
 
	}
 
}

输出结果如下:

startDate : Thu Oct 10 11:30:10 SGT 2013
endDate : Sun Oct 13 20:35:55 SGT 2013
different : 291945000
3 days, 9 hours, 5 minutes, 45 seconds

看看这里的输出，并没有年，月的差别。手工计算是件麻烦事，所以一般采用了 joda time library 来实现，

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
 
import org.joda.time.Interval;
import org.joda.time.Period;
 
public class DateTimeUtils {
 
	public static void main(String[] args) {
 
	  DateTimeUtils obj = new DateTimeUtils();
	  SimpleDateFormat simpleDateFormat = 
               new SimpleDateFormat("dd/M/yyyy hh:mm:ss");
 
	  try {
 
		Date date1 = simpleDateFormat.parse("10/10/2013 11:30:10");
		Date date2 = simpleDateFormat.parse("13/11/2014 20:35:55");
 
		obj.printDifference(date1, date2);	
 
	  } catch (ParseException e) {
		e.printStackTrace();
	  }
 
	}
 
	public void printDifference(Date startDate, Date endDate){
 
	  Interval interval = 
               new Interval(startDate.getTime(), endDate.getTime());
	  Period period = interval.toPeriod();
 
          System.out.printf(
	       "%d years, %d months, %d days, %d hours, %d minutes, %d seconds%n", 
	       period.getYears(), period.getMonths(), period.getDays(),
	       period.getHours(), period.getMinutes(), period.getSeconds());
 
	}
}

看看结果

1 years, 1 months, 3 days, 9 hours, 5 minutes, 45 seconds

还可以参考以下文章：
java 计算时间差
java 时区转换 计算

From：一号门