请教2个日期相减，如何得到年

Question

Calendar.getInstanse().setTime(Date1.getTime()-Date2.getTime()).get(Calendar.YEAR);

Answer 1

public class TestDate
{
    public TestDate()
    {
    }
    public static java.util.Date getDateTime(String dateString)
        throws java.text.ParseException
    {
        if(dateString ==null || dateString.equals(""))
        {
            return null;
        }
        java.text.SimpleDateFormat
            simpleDateFormat =new java.text.SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        return simpleDateFormat.parse(dateString);
    }
    public static void main(String[] args) throws Exception
    {
        java.util.Date Date1 = getDateTime("2002-01-02 00:00:00");
        java.util.Date Date2 = getDateTime("2001-01-01 00:00:00");
        java.util.Calendar c = java.util.Calendar.getInstance();
        c.setTimeInMillis(  Date1.getTime()-Date2.getTime() );
        int yy = c.get(java.util.Calendar.YEAR)-1970;
        int mm = c.get(java.util.Calendar.MONTH);
        int dd = c.get(java.util.Calendar.DAY_OF_MONTH)-1;
        System.out.println("YEARS:"+yy+" MONTHS:"+mm+" DAYS: "+dd);
    }
}

Answer 2

public class TestDateFunc
{
    public static java.util.Date getDateTime(String dateString)
        throws java.text.ParseException
    {
        if(dateString ==null || dateString.equals(""))
        {
            return null;
        }
        java.text.SimpleDateFormat
            simpleDateFormat =new java.text.SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        return simpleDateFormat.parse(dateString);
    }
    public long DateDiff(java.util.Date Date1,java.util.Date Date2)
    {
        class Distance
        {
            public java.util.Date getDateTime(String dateString)
                throws java.text.ParseException
            {
                if(dateString ==null || dateString.equals(""))
                {
                    return null;
                }
                java.text.SimpleDateFormat
                    simpleDateFormat =new java.text.SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
                return simpleDateFormat.parse(dateString);
            }
            public int getDiff(java.util.Date Date1,java.util.Date Date2)
                {
                    java.util.Calendar c = java.util.Calendar.getInstance();
                    c.setTimeInMillis(  Date1.getTime()-Date2.getTime() );
                    int yy = c.get(java.util.Calendar.YEAR)-1970;
                    int mm = c.get(java.util.Calendar.MONTH);
                    int dd = c.get(java.util.Calendar.DAY_OF_MONTH)-1;
                    return yy;
                }
        }
        Distance p = new Distance();
        return p.getDiff(Date1,Date2);
    }
    public static void main(String[] args) throws Exception
    {
        TestDateFunc t = new TestDateFunc();
        java.util.Date Date1 = getDateTime("2004-01-02 00:00:00");
        java.util.Date Date2 = getDateTime("2001-01-01 00:00:00");        System.out.println(t.DateDiff(Date1,Date2)) ;
    }}