//整型变量，表示难度等级为：简单 public static final int EASY = 1; //整型变量，表示难度等级为：普通 public static final int NATURAL = 2; //整型变量，表示难度等级为：难 public static final int HARD = 3; //设定初始难度等级为简单 private int grade = Spider.EASY; private Container pane = null; //生成纸牌数组 priv