Java封裝的與當前時間比較，獲得多少年，多少月，多少天前,多少小時前，多小分鐘前

public class CalendarCal {
 /**
  * 與當前時間比較，獲得多少年，多少月，多少天前,多少小時前，多小分鐘前
  *
  * @param calendar
  *            與當前時間比較的日期值
  * @return 格式化以後的字符串
  */
 public String getDateCompareNow(Calendar calendar) {
  Calendar cal = Calendar.getInstance();
  int year = cal.get(Calendar.YEAR) - calendar.get(Calendar.YEAR);
  String strdate = null;
  if (year > 0) {
   strdate = year + "年前";
  } else if (year == 0) {
   int month = cal.get(Calendar.MONTH) - calendar.get(Calendar.MONTH);
   if (month > 0) {
    strdate = month + "月前";
   } else if (month == 0) {
    int day = cal.get(Calendar.DAY_OF_MONTH) - calendar.get(Calendar.DAY_OF_MONTH);
    if (day > 0) {
     strdate = day + "天前";
    } else if (day == 0) {
     int hour = cal.get(Calendar.HOUR_OF_DAY) - calendar.get(Calendar.HOUR_OF_DAY);
     if (hour > 0) {
      strdate = hour + "小時前";
     } else if (hour == 0) {
      int minute = cal.get(Calendar.HOUR_OF_DAY) - calendar.get(Calendar.HOUR_OF_DAY);
      if (minute > 0) {
       strdate = minute + "分鐘前";
      } else if (minute == 0) {
       strdate = "剛剛";
      }
     }
     // SimpleDateFormat sdf = new SimpleDateFormat("HH:mm"); //
     // 格式化對象
     // strdate = sdf.format(calendar.getTime()); // 輸出格式化的日期
     // strdate = DateUtil.dateToString(date,"HH:mm");
    }
   }
  } else {
   return "-1"; // 返回了一個負數
  }
  return strdate;
 }
 /**
  * 測試代碼
  * @param args
  * @throws ParseException
  */
 public static void main(String[] args) throws ParseException{
  SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
  Date date = sdf.parse("2013-10-02 15:53:10");
  Calendar calendar = Calendar.getInstance(); // 日曆對象
  calendar.setTime(date); // 設置當前日期
  CalendarCal t = new CalendarCal();
  String strdate = t.getDateCompareNow(calendar);
  System.out.println(strdate);
 }
}