求算法，知道怎么求出两个日期的年，天，时，分，秒，就是月份不知道怎么算，搜索了所有的日期文章都没涉及到！！

Question

Date d1,d2;
Calendar cal1=new GregorianCalendar();
cal1.setTime(d1);
Calendar cal2=new GregorianCalendar();
cal2.setTime(d2);
int k=cal1.get(Calendar.YEAR)*12+cal1.get(Calendar.MONTH)-cal1.get(Calendar.YEAR)*12-cal1.get(Calendar.MONTH);
//两个时间差多少个月

Answer 1

打错了：
int k=cal1.get(Calendar.YEAR)*12+cal1.get(Calendar.MONTH)-cal2.get(Calendar.YEAR)*12-cal2.get(Calendar.MONTH);

Answer 2

Calendar calendar = Calendar.getInstance();
        Date d=new Date();
        calendar.setTime(d);
        String theyear=Integer.toString(calendar.get(Calendar.YEAR));
        String themonth=myconvert(Integer.toString(calendar.get(Calendar.MONTH)+1));
        String theday=myconvert(Integer.toString(calendar.get(Calendar.DAY_OF_MONTH)));
        String thehour=myconvert(Integer.toString(calendar.get(Calendar.HOUR_OF_DAY)));
        String theminute=myconvert(Integer.toString(calendar.get(Calendar.MINUTE)));
        String thesecond=myconvert(Integer.toString(calendar.get(Calendar.SECOND)));
        String stoday=theyear+themonth+theday+"-"+thehour+theminute+thesecond;

Answer 3

Calendar类里面什么都有，你看看api，建议不要使用date类

Answer 4

下面转一篇：
来源：http://search.csdn.net/Expert/topic/2492/2492629.xml?temp=.3503229我丢人啊，我不活啦。这么EASY的问题居然连贴俩贴都有虫虫。我可是三天学完JAVA，还懂.jar的啊。昨日按SQLSERVER 的 dateDiff() 测试了一下代码，修正了大大小小一堆bug。最终版本如下。当当当当，隆重推出 dateDiff()。/*
 * @(#)DateDiff.java  1.00 11/26/2003
 *
 */
import java.util.Calendar;
/**
  * 
  *
  * Copyright 2003 Wobelisk. All rights reserved.
  * Free Use. No response for damage caused by errors of this file.  
  * <p>
  * dateDiff() function similar to ms sqlserver. Calculate difference between two
  * Calendars. Difference can be represented by day,week,hour,minute and second.
  * 
  * <p>
  * The difference between "2003-11-22 23:59:59" and "2003-11-23 00:00:00" is
  * 1 day, or 1 week, or 1 hour, or 1 minute or 1 second
  * <p>
  * Default week difference is based on the rule that Sunday as the first day of
  * the week. In France or China where Monday is the first day of week, you
  * should set the first day of week to Monday before calculation. For Example,
  * <pre>
  * Calendar c1=Calendar.getInstance();
  * Calendar c2=Calendar.getInstance();
  * c1.set(2003,10,23,23,0,0); //Sunday 2003-11-23 23:00:00
  * c2.set(2003,10,24,1,0,0);  //Monday 2003-11-24 01:00:00
  * dateDiff("week",c1,c2);    //week difference between c1 and c2 is 0 week
  * c1.setFirstDayOfWeek(Calendar.MONDAY);
  * c2.setFirstDayOfWeek(Calendar.MONDAY);
  * dateDiff("week",c1,c2);    //week difference between c1 and c2 is 1 week
  * </pre>
  *
  * setFirstDayOfWeek() only affects week difference
  *
  * @author [email protected]
  * @version 1.00 11/26/2003
  *
  */ 
  public class DateDiff{
      /**
   * Calculate Calendar c2 - Calendar c1
   * @param s the String represents type of difference: day, week, hour, 
   * minute, second. String is case-insensitive
   * @param c1 the Calendar instance
   * @param c2 the Calendar instance
   */    public static long dateDiff(String s,Calendar c1, Calendar c2){
     String s1=s.toUpperCase();
     if(s1.equals("DAY")){
        Calendar c11=Calendar.getInstance();
        Calendar c21=Calendar.getInstance();
        c11.set(c1.get(Calendar.YEAR),c1.get(Calendar.MONTH),c1.get(Calendar.DAY_OF_MONTH),0,0,0); 
        c21.set(c2.get(Calendar.YEAR),c2.get(Calendar.MONTH),c2.get(Calendar.DAY_OF_MONTH),0,0,0); 
        return (c21.getTimeInMillis()-c11.getTimeInMillis())/(1000*24*3600);  
   } else if(s1.equals("WEEK")){
        long base=dateDiff("DAY",c1,c2);
        int dw1=c1.get(Calendar.DAY_OF_WEEK);
        int dw2=c2.get(Calendar.DAY_OF_WEEK);

        if(c1.getFirstDayOfWeek()==Calendar.MONDAY && dw1==Calendar.SUNDAY)
   dw1+=7;
        if(c2.getFirstDayOfWeek()==Calendar.MONDAY && dw2==Calendar.SUNDAY)
   dw2+=7;
if(base>0 && dw2<dw1)
   return base/7+1;
else if(base<0 && dw2>dw1)
  return base/7-1;
else 
  return base/7;
    } else if(s1.equals("HOUR")){
return dateDiff("DAY",c1,c2)*24+c2.get(Calendar.HOUR_OF_DAY)-c1.get(Calendar.HOUR_OF_DAY);
   } else if(s1.equals("MINUTE")){
return dateDiff("HOUR",c1,c2)*60+c2.get(Calendar.MINUTE)-c1.get (Calendar.MINUTE);
  } else if(s1.equals("SECOND")){
return dateDiff("MINUTE",c1,c2)*60+c2.get(Calendar.SECOND)-c1.get(Calendar.SECOND);
  } else
return Long.MIN_VALUE; //error
 }
}

Answer 5

TO:
flyxxxxx(灭神) ( ) 
我觉得你的方法不正确！你没有考虑过"2004-1-2" 和"2005-1-1"实际上只有11个月，而不是12个月，你明白我的意思没有！！！
大家再好好想想！！

Answer 6

java.text.SimpleDateFormat df = new java.text.SimpleDateFormat("yyyy-MM-dd");
java.util.Date d1 = df.parse("2004-1-2");
java.util.Date d2 = df.parse("2005-1-1");java.util.GregorianCalendar cal1=new java.util.GregorianCalendar();
cal1.setTime(d1);
java.util.GregorianCalendar cal2=new java.util.GregorianCalendar();
cal2.setTime(d2);
int k=(cal2.get(java.util.Calendar.YEAR)-cal1.get(java.util.Calendar.YEAR))*12+cal2.get(java.util.Calendar.MONTH)-cal1.get(java.util.Calendar.MONTH);
int mod = cal2.get(java.util.Calendar.DATE)-cal1.get(java.util.Calendar.DATE);
k+=(mod>0?1:(mod<0?-1:0));
System.out.println(k);

Answer 7

楼上，还是不对！
java.util.Date d1 = df.parse("2004-1-2");
java.util.Date d2 = df.parse("2005-1-4");
试试看，就知道了！！！请问，是不是我太专牛角了！好象如果要考虑天的话，很难算出来是不是各位？！！

Answer 8

java.text.SimpleDateFormat df = new java.text.SimpleDateFormat("yyyy-MM-dd");
java.util.Date d1 = df.parse("2004-1-2");
java.util.Date d2 = df.parse("2005-1-1");java.util.GregorianCalendar cal1=new java.util.GregorianCalendar();
cal1.setTime(d1);
java.util.GregorianCalendar cal2=new java.util.GregorianCalendar();
cal2.setTime(d2);
int k=(cal2.get(java.util.Calendar.YEAR)-cal1.get(java.util.Calendar.YEAR))*12+cal2.get(java.util.Calendar.MONTH)-cal1.get(java.util.Calendar.MONTH);
int mod = cal2.get(java.util.Calendar.DATE)-cal1.get(java.util.Calendar.DATE);
k+=(mod>=0?0:-1);
System.out.println(k);