Java 日期时间格式化显示一年中的第几周

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 " + cl.WEEK_OF_YEAR+ " week of the year");
      System.out.println("today is a "+cl.DAY_OF_MONTH + "month of the year");
      System.out.println("today is a "+cl.WEEK_OF_MONTH +"week of the month");
   }
}