java - 计算Date Java多久了

我有一个功能：

  public String getTimePast(Date d) {
  //insertcodehere
 }

它接受消息的日期，并且必须以特定格式返回基于当前时间的过去时间。例如，如果它刚刚发布，它会说“现在”
如果是4分钟，就会说“4分钟”
如果是23小时，它会说“23小时”
等
下面是我如何试图做它没有运气！我怎么能做到这一点？谢谢您！

public String getTimePast(Date d) {


    Calendar c = Calendar.getInstance();

    int hr = c.get(Calendar.HOUR_OF_DAY);
    int min = c.get(Calendar.MINUTE);
    int day = c.get(Calendar.DAY_OF_MONTH);
    int month = c.get(Calendar.MONTH);
    int year = c.get(Calendar.YEAR);


    if (year == d.getYear()) {
        if (month == d.getMonth()) {
            if (day == d.getDay()) {
                if (hr == d.getHours()) {
                    if (min == d.getMinutes()) {
                        return "Now";
                    } else {
                        return min - d.getMinutes() + "m";
                    }
                } else {
                    return hr - d.getHours() + "hr";

                }
            } else {
                return day - d.getDay() + "d";
            }
        } else {
            return month - d.getMonth() + "m";
        }
    } else {
        return year - d.getYear() + "y";
    }


}

最佳答案

不如使用另一个日历对象作为简单的差异

Calendar now = Calendar.getInstance();
Calendar start = Calendar.getInstance();
start.setTime (d);

long milliseconds1 = start.getTimeInMillis();
  long milliseconds2 = now.getTimeInMillis();
  long diff = milliseconds2 - milliseconds1;
  long diffSeconds = diff / 1000;
  long diffMinutes = diff / (60 * 1000);
  long diffHours = diff / (60 * 60 * 1000);
  long diffDays = diff / (24 * 60 * 60 * 1000);
  System.out.println("\nThe Date Different Example");
  System.out.println("Time in milliseconds: " + diff
 + " milliseconds.");
  System.out.println("Time in seconds: " + diffSeconds
 + " seconds.");
  System.out.println("Time in minutes: " + diffMinutes
+ " minutes.");
  System.out.println("Time in hours: " + diffHours
+ " hours.");
  System.out.println("Time in days: " + diffDays
+ " days.");
  }

参见http://www.roseindia.net/java/beginners/DateDifferent.shtml