Java,要求具体过程(用构造方法)

public class Card{
  private String color;
  private int pointNum;
  public Card(String color,int pointNum){
    this.color=color;
    this.pointNum=pointNum;
  }
  public void showCard(){
    System.out.println("牌色"+color +",点数"+pointNum);
  }
  public static void main(String []args){
    Card card=new Card("白色",4);
    card.showCard();
  }
}