Java Data Type - 如何将java.sql.Date对象转换为GregorianCalendar

import java.sql.Date;
import java.util.Calendar;
import java.util.GregorianCalendar;

public class Main {

  public static void main(String[] args) {
    Date date = Date.valueOf("2015-12-25");
    System.out.println(date);

    Calendar cal = new GregorianCalendar();
    cal.setTime(date);
    System.out.println(cal.getTime());
  }
}