java - 以月、周或天为单位查找年龄

Question

我有一些java代码可以查找一个人的日期。它看起来像这样:

  Calendar now = Calendar.getInstance();
  Calendar dob = Calendar.getInstance();

  dob.setTime(birthDay); /*assume this is not null */

  int age = now.get(Calendar.YEAR) - dob.get(Calendar.YEAR);

  if (now.get(Calendar.DAY_OF_YEAR) < dob.get(Calendar.DAY_OF_YEAR)) 
  {
    age--;
  }

现在，我想说如果这个人不到 1 岁，找出这个人有多少个月。如果此人不到 1 个月大，请找出此人有多少周了。如果此人出生不到 1 周，请查明此人出生了多少天。

伪代码:

if (age < 1)
{
    ///?
}

Answer 1

类似于:

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;


public class TimeDiff {

    public static void main(String[] args) throws ParseException {
        Date now = new Date();
        System.out.println(now);
        Date birthDate = new SimpleDateFormat("dd-MM-yyyy").parse("7-12-1983");
        System.out.println(birthDate);

        Date age = new Date(now.getTime() - birthDate.getTime());
        Calendar instance = Calendar.getInstance();
        instance.setTime(age);
        instance.add(Calendar.YEAR, -1970);
        SimpleDateFormat sdf = new SimpleDateFormat("d-W-MM-yyyy");
        System.out.println(sdf.format(instance.getTime()));
    }

}