Java 日期时间格式化-添加时间到日期

import java.util.*;

public class Main {
   public static void main(String[] args) throws Exception {
      Date d1 = new Date();
      Calendar cl = Calendar.getInstance();
      cl.setTime(d1);
      System.out.println("today is " + d1.toString());
      cl.add(Calendar.MONTH, 1);
      System.out.println("date after a month will be " + cl.getTime().toString() );
      cl.add(Calendar.HOUR, 70);
      System.out.println("date after 7 hrs will be " + cl.getTime().toString() );
      cl.add(Calendar.YEAR, 3);
      System.out.println("date after 3 years will be " + cl.getTime().toString() );
   }
}