Java Data Type - 如何添加day到日期数据

import java.util.Calendar;
import java.util.Date;

public class Main {

  public static void main(String[] args) {
    System.out.println(addDays(new Date(), 100));
  }

  public static Date addDays(Date date, Integer days) {
    Calendar cal = Calendar.getInstance();
    cal.setTime(date);
    cal.add(Calendar.DAY_OF_MONTH, days);
    return cal.getTime();
  }

}