获得两个日期差，差的形式为：XX天XX小时XX分XX秒

DateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
try

{

  Date d1 = df.parse("2004-03-26 13:31:40");

  Date d2 = df.parse("2004-01-02 11:30:24");
  long diff = d1.getTime() - d2.getTime();//这样得到的差值是微秒级别
  long days = diff / (1000 * 60 * 60 * 24);

  long hours = (diff-days*(1000 * 60 * 60 * 24))/(1000* 60 * 60);
  long minutes = (diff-days*(1000 * 60 * 60 * 24)-hours*(1000* 60 * 60))/(1000* 60);
  System.out.println(""+days+"天"+hours+"小时"+minutes+"分");

}
catch (Exception e)
{
}